(-)-Carvone Inhibits Oxytocin-induced Writhing Via Uterine Relaxation in Rodents.

(-)-Carvone, a ketone monoterpene, is the main component of essential oils from several medicinal plants and has been reported to have anti-arthriric, anticonvulsive, antidiabetic, anti-inflammatory, anticancer, and immunomodulatory effects. Therefore, this study aimed to investigate the spasmolytic activity of (-)-carvone in rodent models. The isolated virgin rat uterus was mounted in an organ bath apparatus, and the relaxing effect of ( -)-carvone and its mechanism of action were evaluated in tonic contractions induced by carbachol, KCl, PGF2α, or oxytocin. The animal model of primary dysmenorrhea was replicated with the injection of estradiol benzoate in female mice for three consecutive days, followed by intraperitoneal administration of oxytocin. Non-clinical acute toxicity evaluation was also performed. (-)-Carvone potency and effectiveness were larger in carbachol (pEC50 = 5.41 ± 0.14 and Emax = 92.63 ± 1.90% at 10-3 M) or oxytocin (pEC50 = 4.29 ± 0.17 and Emax = 86.69 ± 1.56% at 10-3 M) contractions. The effect of ( -)-carvone was altered in the presence of 4-aminopyridine, glibenclamide, L-NAME, or methylene blue. Mice pre-treated with (-)-carvone at a dose of 100 mg/kg showed a significant reduction in the number of writhing after oxytocin administration. No toxicity was observed after oral administration of 1 g/kg ( -)-carvone. Taken together, we showed that (-)-carvone reduced writhing by a spasmolytic effect, probably through the participation of KV and KATP channels and the nitric oxide pathway.

Smooth muscle contraction of the fundus of stomach, duodenum and bladder from mice exposed to a stress-based model of depression.

Several reports have demonstrated that depressive disorder is related to somatic symptoms including gastrointestinal or genitourinary alterations. The pathophysiological mechanisms underlying the gastrointestinal or genitourinary alterations associated with the depression are still not fully understood. Therefore, this study aimed to evaluate the motor activity of gastrointestinal (fundus of stomach and duodenum) and genitourinary tract (bladder) in a stress-based animal model of depression. Adult male mice were submitted to uncontrollable and unpredictable stress (learned helplessness model), controllable stress and non-stressful situations (control). Then, animals were euthanized and the fundus of stomach, duodenum segments or whole bladder were isolated and mounted in a standard organ bath preparation. We evaluated the contractile effects induced by KCl 80 mM for 5 min or carbachol (acetylcholine receptor agonist). The relaxant effects of isoproterenol (ß-adrenoceptor agonist) were also checked. Animals submitted to the learned helplessness model developed a helpless (depressive-like behavior) or resilient (does not exhibit depressive-like behavior) phenotype. The contractions induced by carbachol were diminished in fundus of stomach isolated from helpless and resilient animals. The isoproterenol-induced fundus of stomach relaxation was reduced in resilient but not helpless mice. The contractions/relaxation of duodenum segments isolated from helpless or resilient animals were not altered. Both helpless and resilient animals showed an increase in the bladder contractions induced by carbachol while the relaxant effects of isoproterenol were reduced when compared to control. Conversely, mice underwent a controllable stress situation did not exhibit alterations in the fundus of stomach or duodenum contraction/relaxation induced by pharmacological agents although a decrease in the bladder contraction induced by carbachol was found. In conclusion, incontrollable and unpredictable stress and not depressive phenotype (helpless animals) or controllable stress could be related to the alterations in motor activity of the fundus of stomach and bladder.

G-protein tonic inhibition of calcium channels in pancreatic ß-cells.

Voltage-gated calcium channels (CaV) conduct Ca2+ influx promoting neurotransmitters and hormone release. CaV are finely regulated by voltage-dependent and independent pathways either by G-protein-coupled receptors (GPCRs) or intramembrane lipids, respectively, in neurons and glands. Interestingly, pancreatic ß-cells are abundantly innervated by both sympathetic and parasympathetic neurons, while a variety of high-voltage activated (HVA) Ca2+ channels are present in these cells. Thus, autonomic system seems to exert a tonic inhibition on HVA Ca2+ channels throughout GPCRs, constitutively preventing hormone secretion. Therefore, this work aimed to investigate noradrenergic and cholinergic inhibition of HVA Ca2+ channels in pancreatic ß-cells. Experiments were conducted in pancreatic ß-cells of rat by using patch-clamping methods, immunocytochemistry, pharmacological probes, and biochemical reagents. A voltage-clamp protocol with a strong depolarizing prepulse was used to unmask tonic inhibition. Herein, we consistently find a basal tonic inhibition of HVA Ca2+ channels according to a GPCRs regulation. Facilitation ratio is enhanced by noradrenaline (NA) according to a voltage-dependent regulation and a membrane-delimited mechanism, while no facilitation changes are observed with carbachol or phosphatidylinositol 4,5-bisphosphate (PIP2). Furthermore, carbachol or intramembrane lipids, such as PIP2, do not change facilitation ratio according to a voltage-independent regulation. Together, HVA Ca2+ channels of pancreatic ß-cells are constitutively inhibited by GPCRs, suggesting a natural brake preventing cells from exhaustive insulin secretion.NEW & NOTEWORTHY Our results support the hypothesis that GPCRs tonically inhibit HVA Ca2+ channels in pancreatic ß-cells. A voltage-clamp protocol with a strong depolarizing prepulse was used to unmask voltage-dependent inhibition of Ca2+ channels. The novelty of these results strengthens the critical role of Gßγ's in Ca2+ channel regulation, highlighting kinetic slowing and increased facilitation ratio. Together, HVA Ca2+ channels of pancreatic ß-cells are constitutively inhibited by GPCRs underlying fine-tuning modulation of insulin secretion.

Co-administration of sodium hydrosulfide and tadalafil modulates hypoxia and oxidative stress on bladder dysfunction in a rat model of bladder outlet obstruction.

PURPOSE: This study aimed to assess the possible healing effect of combination treatment with a hydrogen sulfide (H2S) donor, sodium hydrosulfide (NaHS) plus tadalafil on partial bladder outlet obstruction (PBOO)-induced bladder dysfunction. MATERIALS AND METHODS: A total of 75 male Sprague-Dawley rats aged 10-wk and 300-350g were divided into five groups; control; PBOO; PBOO+NaHS (5.6mg/kg/day, i.p., 6-wk); PBOO+tadalafil (2mg/kg/day, oral, 6-wk) and PBOO+NaHS+tadalafil. PBOO was created by partial urethral ligation. 6 weeks after obstruction, the in vitro contractile responses of the detrusor muscle and Western blotting, H2S and malondialdehyde assay were performed in bladder tissues. RESULTS: There was an increase in bladder weight(p<0.001) and a decrease in contractile responses to KCL(p<0.001), carbachol(p<0.01), electrical field stimulation(p<0.05) and ATP (p<0.001) in the detrusor smooth muscle of obstructed rats which was normalized after the combination treatment. Cystathionine γ-lyase and cystathionine ß-synthase, and nuclear factor kappa B protein levels did not significantly differ among groups. The obstruction induced decrement in 3-mercaptopyruvate sulfur transferase protein expression(p<0.001) and H2S levels(p<0.01) as well as increment in protein expressions of neuronal nitric oxide synthase (NO, p<0.001), endothelial NOS (p<0.05), inducible NOS(p<0.001), hypoxia-inducible factor 1-alpha (p<0.01), and malondialdehyde levels (p<0.01), when combined treatment entirely normalized. CONCLUSIONS: Combination therapy has beneficial effects on bladder dysfunction via regulating both H2S and nitric oxide pathways as well as downregulation of oxidative stress and hypoxia. The synergistic effect of H2S and nitric oxide is likely to modulate bladder function, which supports the combined therapy for enhancing clinical outcomes in men with BPH/LUTS.

Nerve Growth Factor: A Dual Activator of Noradrenergic and Cholinergic Systems of the Rat Ovary.

The functioning of the ovary is influenced by the autonomic system (sympathetic and cholinergic intraovarian system) which contributes to the regulation of steroid secretion, follicular development, and ovulation. There is no information on the primary signal that activates both systems. The nerve growth factor (NGF) was the first neurotrophic factor found to regulate ovarian noradrenergic neurons and the cholinergic neurons in the central nervous system. The aim of this study was to determine whether NGF is one of the participating neurotrophic factors in the activation of the sympathetic and cholinergic system of the ovary in vivo and its role in follicular development during normal or pathological states. The administration of estradiol valerate (a polycystic ovary [PCO] phenotype model) increased norepinephrine (NE) (through an NGF-dependent mechanism) and acetylcholine (ACh) levels. Intraovarian exposure of rats for 28 days to NGF (by means of an osmotic minipump) increased the expression of tyrosine hydroxylase and acetylcholinesterase (AChE, the enzyme that degrades ACh) without affecting enzyme activity but reduced ovarian ACh levels. In vitro exposure of the ovary to NGF (100 ng/ml for 3 h) increased both choline acetyl transferase and vesicular ACh transporter expression in the ovary, with no effect in ACh level. In vivo NGF led to an anovulatory condition with the appearance of follicular cysts and decreased number of corpora lutea (corresponding to noradrenergic activation). To determine whether the predominance of a NE-induced polycystic condition after NGF is responsible for the PCO phenotype, rats were exposed to an intraovarian administration of carbachol (100 µM), a muscarinic cholinergic agonist not degraded by AChE. Decreased the number of follicular cysts and increased the number of corpora lutea, reinforcing that cholinergic activity of the ovary participates in controlling its functions. Although NGF increased the biosynthetic capacity for ACh, it was not available to act in the ovary. Hence, NGF also regulates the ovarian cholinergic system, implying that NGF is the main regulator of the dual autonomic control. These findings highlight the need for research in the treatment of PCO syndrome by modification of locally produced ACh as an in vivo regulator of follicular development.

Pharmacological screening of the phenolic compound caffeic acid using rat aorta, uterus and ileum smooth muscle.

Caffeic acid is a phenolic compound widely found in commonly consumed foods such as pears, apples and coffee, and is pharmacologically known for its antioxidant, anti-inflammatory and anti-asthmatic properties. However, its relaxant activity in the aorta, uterus and ileum smooth muscle has not been investigated. This study aimed to comparatively evaluate the effect of caffeic acid on smooth muscle from different organs (aorta, uterus and ileum), and the contractions of this different organ were induced by different agonists. The organ bath technique was used, where the organs were placed in different cuvettes with 10 mL of Tyrode solution for 1 h to stabilize, then, myometrial, intestinal strip and aortic ring contractions were evoked using different contractile agonists (KCl 60 mM, PHE 0.1 µM, OT 10-2 IU/mL, CCh 10-6 M and BaCl2 0.1-30 mM); increasing concentrations of caffeic acid (0.03-7 mM) were administered in the experimental preparations. In the presence of KCl (60 mM), caffeic acid caused relaxations with the following EC50 values: 2.7 ± 0.26 mM/mL (aorta), 5.7 ± 0.71 mM/mL (uterus) and 2.1 ± 0.39 mM/mL (ileum). When in the presence of different agonists, PHE (0.1 µM) for the aorta, OT (10-2 IU/mL) for the uterus and CCh (10-6 M) for the ileum, caffeic acid caused relaxations with EC50 values of: 2.7 ± 0.31 mM/mL; 2.2 ± 0.34 mM/mL and 2.0 ± 0.28 mM/mL, respectively. The inhibitory effect of caffeic acid on serotonergic (aorta and uterus) and muscarinic receptors (uterus and ileum), as well as its possible involvement with L-type Ca2+ channels, was also observed. This study reports the pharmacological characterization of caffeic acid on smooth muscle from different organs, for which caffeic acid was more potent in the ileum. A diverse understanding of its performance as a possible therapeutic product is attributed to its relaxant effect.

The metronomic combination of paclitaxel with cholinergic agonists inhibits triple negative breast tumor progression. Participation of M2 receptor subtype.

Triple negative tumors are more aggressive than other breast cancer subtypes and there is a lack of specific therapeutic targets on them. Since muscarinic receptors have been linked to tumor progression, we investigated the effect of metronomic therapy employing a traditional anti-cancer drug, paclitaxel plus muscarinic agonists at low doses on this type of tumor. We observed that MDA-MB231 tumor cells express muscarinic receptors, while they are absent in the non-tumorigenic MCF-10A cell line, which was used as control. The addition of carbachol or arecaidine propargyl ester, a non-selective or a selective subtype 2 muscarinic receptor agonist respectively, plus paclitaxel reduces cell viability involving a down-regulation in the expression of ATP "binding cassette" G2 drug transporter and epidermal growth factor receptor. We also detected an inhibition of tumor cell migration and anti-angiogenic effects produced by those drug combinations in vitro and in vivo (in NUDE mice) respectively. Our findings provide substantial evidence about subtype 2 muscarinic receptors as therapeutic targets for the treatment of triple negative tumors.

Effect of low dose metronomic therapy on MCF-7 tumor cells growth and angiogenesis. Role of muscarinic acetylcholine receptors.

The non-neuronal cholinergic system refers to the presence of acetylcholine, choline acetyltransferase, acetylcholinesterase and cholinergic receptors, nicotinic and muscarinic (mAChRs) expressed in non-neuronal cells. The presence of mAChRs has been detected in different type of tumor cells and they are linked with tumorigenesis. We had previously documented the expression of mAChRs in murine and human mammary adenocarcinomas and the absence of these receptors in normal mammary cells of the same origins. We also demonstrated that mAChRs are involved in breast cancer progression, pointing to a main role for mAChRs as oncogenic proteins. Since the long term treatment of breast cancer cells with the muscarinic agonist carbachol promoted cell death, here we investigated the ability of low doses of this agonist combined with paclitaxel (PX), a taxane usually administered to treat breast cancer, to inhibit the progression of human MCF-7 tumor cells. We demonstrated that PX plus carbachol reduced cell viability and tumor growth in vitro probably due to a down-regulation in cancer stem cells population and in the expression of ATP "binding cassette" G2 drug extrusion pump; also a reduction in malignant-induced angiogenesis was produced by the in vivo administration of the mentioned combination in a metronomic schedule to MCF-7 tumor-bearing NUDE mice. Our results confirm that mAChRs could be considered as therapeutic targets for metronomic therapy in breast cancer as well as the usefulness of a muscarinic agonist as repositioning drug in the treatment of this type of tumors.

Efeitos de análogos da acetilcolina e noradrenalina sobre interações entre timócitos e células epiteliais tímicas / Effects of acetylcholine and norepinephrine analogs on interactions between thymocytes and thymic epithelial cells

O timo é um órgão linfoide primário responsável pelo desenvolvimento e seleção de células T. Diversos fatores podem afetar o desenvolvimento de células T, como citocinas, quimiocinas e moléculas da matriz extracelular, mas também hormônios, neuropeptídeos e neurotransmissores. O timo recebe densa inervação simpática, liberando majoritariamente noradrenalina (NA), timócitos e células tímicas não linfoides expressam receptores adrenérgicos e podem sintetizar catecolaminas, sugerindo modulação de NA por diferentes vias. Por outro lado, poucas evidências anatômicas suportam a hipótese da inervação tímica parassimpática. Entretanto, acetilcolina (ACh) parece ser endogenamente produzida no órgão, uma vez que diferentes células no timo expressam a enzima sintetizadora de ACh (ChAT) e receptores colinérgicos. Sendo assim, o objetivo deste trabalho foi determinar o papel funcional de ACh e NA sobre os componentes linfoide e microambiental do timo, e sobre as interações entre células epiteliais e timócitos. Avaliamos a expressão de receptores adrenérgicos α1A, α1D, α2C, ß2 e colinérgicos M1, M3, M5 e α7 em timócitos e TECs, através do método de PCR quantitativa. Todas as populações celulares testadas expressavam os receptores selecionados.

Além disso, buscamos caracterizar o efeito de drogas análogas aos neurotransmissores sobre a morte e a proliferação de timócitos, através da marcação com anexina-V/iodeto de propídio (IP) e CFSE respectivamente. Timócitos obtidos do timo de camundongos C57BL/6 fêmeas, foram tratados com carbacol (análogo de Ach - em concentrações variando de 10 nM a 1000 nM) ou arterenol (análogo de NA - em concentrações variando de 10 nM a 1 mM). Verificamos que apenas arterenol na concentração de 1 mM induziu a apoptose nas células tratadas. Nenhum dos análogos modulou a proliferação celular. Avaliamos ainda o efeito das drogas sobre a migração de timócitos, agindo como quimioatrente ou modulando a migração induzida por fibronectina. Nenhuma das drogas demonstrou efeito quimioatraente ou alterou a migração induzida por fibronectina. Além disso, avaliamos o efeito das drogas sobre a interação TEC/timócitos atraves de ensaios de adesão e observamos que carbacol foi capaz de diminuir a adesão de timócitos a TECs em todas as concentrações testadas. Essa diminuição é refletida no número de timócitos que aderem às TECs e parece estar associada a modulação da expressão do receptor de laminina VLA-6. Nossos dados sugerem que timócitos e as linhagens de TECs testadas expressam receptores e que neurotransmissores, em especial a ACh, podem modular a interação entre TECs e timócitos. (AU)

Effects of obesity induced by high-calorie diet and its treatment with exenatide on muscarinic acetylcholine receptors in rat hippocampus.

Here, we described the effects of obesity induced by high-calorie diet and its treatment with exenatide, an anti-diabetogenic and potential anti-obesogenic drug derived from the venom of the Gila monster Heloderma suspectum, on the affinity, density, subtypes and intracellular signaling pathways linked to activation of muscarinic acetylcholine receptors (mAChRs) in rat hippocampus. Male Wistar rats were divided into three groups: control (CT), obese induced by high-calorie diet (DIO) and DIO treated with exenatide (DIO + E). [3H]Quinuclidinyl benzilate specific binding analysis showed that the equilibrium dissociation constant (KD) did not differ among CT, DIO and DIO + E, indicating that affinity is not affected by high-calorie diet or its treatment with exenatide. On the other hand, the density of mAChRs obtained in DIO animals was lower than that obtained from CT rats, and that DIO + E restored the density of mAChRs. Immunoprecipitation assays reveal a decrease in the expression of M1 and M3 subtypes of DIO animals when compared with CT. Treatment with exenatide (DIO + E) restored the expression of the two subtypes similar to obtained from CT. On the other hand, the M2, M4 and M5 mAChR subtypes expression did not differ among CT, DIO and DIO + E. Carbacol caused a concentration-dependent increase in the accumulation of total [3H] inositol phosphate in CT, DIO and DIO + E. However, the magnitude of the maximal response to carbachol was lower in DIO when compared with those obtained from CT and DIO + E animals, which did not differ from each other. Our results indicate that obesity induced by high-calorie diet strongly influences the expression and intracellular signaling coupled to M1-M3 mAChR subtypes. The exenatide ameliorated these effects, suggesting an important role on hippocampal muscarinic cholinergic system. This action of obesity induced by high-calorie diet and its treatment with exenatide might be a key step mediating cellular events important for learning and memory.

Catalase blockade reduces the pressor response to central cholinergic activation.

Intracerebroventricular (icv) injection of hydrogen peroxide (H2O2), a reactive oxygen species, or the blockade of catalase (enzyme that degrades H2O2 into H2O and O2) with icv injection of 3-amino-1,2,4-triazole (ATZ) reduces the pressor effects of angiotensin II also injected icv. In the present study, we investigated the effects of ATZ injected icv or intravenously (iv) on the pressor responses induced by icv injections of the cholinergic agonist carbachol, which similar to angiotensin II induces pressor responses that depend on sympathoexcitation and vasopressin release. In addition, the effects of H2O2 icv on the pressor responses to icv carbachol were also tested to compare with the effects of ATZ. Normotensive non-anesthetized male Holtzman rats (280-300 g, n = 8-9/group) with stainless steel cannulas implanted in the lateral ventricle were used. Previous injection of ATZ (5 nmol/1 µl) or H2O2 (5 µmol/1 µl) icv similarly reduced the pressor responses induced by carbachol (4 nmol/1 µl) injected icv (13 ± 4 and 12 ± 4 mmHg, respectively, vs. vehicle + carbachol: 30 ± 5 mmHg). ATZ (3.6 mmol/kg of body weight) injected iv also reduced icv carbachol-induced pressor responses (21 ± 2 mmHg). ATZ icv or iv and H2O2 icv injected alone produced no effect on baseline arterial pressure. The treatments also produced no significant change of heart rate. The results show that ATZ icv or iv reduced the pressor responses to icv carbachol, suggesting that endogenous H2O2 acting centrally inhibits the pressor mechanisms (sympathoactivation and/or vasopressin release) activated by central cholinergic stimulation.

Treatment with Paracetamol is not Associated with Increased Airway Sensitivity and Risk of Asthma in Rats.

BACKGROUND: Some studies have linked the use of paracetamol (PAR) with adverse effects like wheezing, exacerbation of asthma symptoms and other respiratory problems. Other studies are inconclusive or deny this correlation. This makes the association between PAR and airway hypersensitivity very controversial and still under debate. OBJECTIVE: This work investigated if chronic treatment with PAR in rats could directly affect the contraction and relaxation for different stimulus in isolated airways. METHODS: Rats were treated for 2 weeks with PAR (400 mg/Kg, v.o.). The blood was collected for biochemical analysis (alanine aminotransferase (ALT), aspartate aminotransferase (AST), TBARs reaction and glutathione) and isolated tracheal rings were prepared in organ bath to measure isometric tone after contractile and relaxant stimulus. RESULTS: Hepatic enzymes (ALT, AST) and lipid peroxidation were increased after PAR-treatment, while glutathione was decreased. Rats do not present any alteration in airway myocytes responsiveness, either to contractile or relaxant stimulus (i.e. cholinergic agonist, membrane depolarization, Ca2+ influx across sarcolemma, internal Ca2+ release from sarcoplasmic reticulum, Ca2+ channel blocking, ß-agonist and NOmediating relaxation). CONCLUSION: Despite increased oxidative stress and reduced antioxidant defense, chronic treatment with PAR does not induce airway hypersensitivity or risk of asthma in rats.

Endogenous hydrogen peroxide affects antidiuresis to cholinergic activation in the medial septal area.

Cholinergic activation of the medial septal area (MSA) with carbachol produces thirst, natriuresis and antidiuresis. Hydrogen peroxide (H2O2) injected into the medial septal area (MSA) impairs behavioral and renal responses induced by carbachol at the same site, suggesting the exogenous H2O2 may modulate the responses to cholinergic activation in the MSA. In the present study, we investigated if the accumulation of endogenous H2O2 in the MSA after the injection of the catalase inhibitor 3-amino-1,2,4-triazole (ATZ) also affects cholinergic responses. In addition, the effects of the combination of ATZ with a non-effective dose of H2O2 in the MSA were also tested. Male Holtzman rats (280-320 g) with stainless steel cannulas implanted in the MSA were used. The treatment with ATZ (10 nmol) into the MSA partially reverted the antidiuretic effect of carbachol (10.5 ± 0.7, vs. saline + carbachol: 7.3 ± 0.6 ml/120 min), without changing carbachol-induced water intake (9.5 ± 1.9, vs. saline + carbachol: 10.7 ± 1.6 ml/60 min). The combination of a low dose of ATZ (2.5 nmol) with an ineffective dose of H2O2 (0.5 µmol) into the MSA reduced carbachol-induced thirst (7.5 ± 2.0, vs. saline + carbachol: 14.9 ± 1.2 ml/15 min) and reverted the antidiuresis (8.1 ± 1.1, vs. saline + carbachol: 5.3 ± 0.9 ml/120 min). Sodium and potassium excretion were not modified regardless the treatment. Although exogenous H2O2 injected in the MSA may affect most of the responses to cholinergic activation of the MSA, the antidiuresis is the response clearly modulated by endogenous H2O2.

Carbacol intraocular para inducción de miosis intraoperatoria durante la cirugía de catarata / Intraocular carbachol for induction of miosis intraoperative during cataract surgery

INTRODUCCIÓN: Este documento técnico se realiza a solicitud de la Gerencia Macro Regional Centro Medio del Seguro Integral de Salud. a) Cuadro clínico: Las cataratas se originan por opacidad del cristalino, lo cual produce una disminución de la agudeza visual. Su desarrollo se relaciona principalmente con la edad, pudiendo afectar hasta un 92,6% de personas a los 80 años. En población pediátrica, las cataratas suelen ser hereditarias o formar parte de un síndrome multisistémico. A nivel mundial, se estima que 95 millones de personas padecen algún tipo de discapacidad visual relacionada con la presencia de cataratas. En Perú la catarata no operada representa la mayor causa de ceguera y deficiencia visual severa en mayores de 50 años. La única terapia efectiva conocida es la extirpación quirúrgica del cristalino y su reemplazo con un lente intraocular, lo cual se indica cuando la pérdida de visión es suficientemente grave para aceptar los riesgos potenciales de la cirugía. Durante el procedimiento quirúrgico, se aplica un agente miótico intraocular con la finalidad de centralizar la pupila, proteger el endotelio del lente implantado, evitar la captura del lente por el iris y el prolapso del iris por las heridas operatorias. b) Tecnología sanitaria: Carbacol es un agente parasimpáticomimetico que produce efecto miótico mediante una acción anticolinérgica y anticolinesterásica. Su uso está indicado durante la cirugía de cataratas, mediante la instilación intraocular de medio mililitro en la cámara anterior, antes o después de asegurar las suturas, obteniendo una miosis satisfactoria dentro de los dos a cinco minutos siguientes a su aplicación. No se ha establecido su seguridad y eficacia en pacientes pediátricos, ni durante el embarazo. Los eventos adversos (EA) reportados incluyen dolor de cabeza, aumento de la presión intraocular, degeneración de la córnea, opacidad corneal, inflamación de la cámara anterior, edema corneal, inflamación ocular, miosis prolongada, visión borrosa, dolor ocular, hiperemia y vómitos. La Food and Drug Administration (FDA) de los Estados Unidos ha aprobado dos medicamentos para la inducción de miosis intraoperatoria, cloruro de acetilcolina y carbacol (Miostat®). En Perú, sólo carbacol cuenta con un registro sanitario con vigencia prorrogada provisional. OBJETIVO: Describir la evidencia científica disponible sobre el uso de carbacol intraocular para inducción de miosis intraoperatoria durante la cirugía de catarata. METODOLOGÍA: Se formuló la siguiente pregunta PICO, P: pacientes con indicación de cirugía de catarata; I: carbacol 0,01% intraocular; C: placebo; O: miosis intraoperatoria, rehabilitación visual, calidad de vida y eventos adversos. Se realizó una búsqueda sistemática en Medline (Pubmed), The Cochrane Library y LILACS. Ésta se complementó con la búsqueda de evidencia en páginas institucionales de agencias gubernamentales y buscadores genéricos. Se priorizó la identificación y selección de revisiones sistemáticas (RS) con o sin meta-análisis, ensayos clínicos aleatorizados (ECAs), estudios observacionales, guías de práctica clínica (GPC), evaluaciones de tecnologías sanitarias (ETS) y evaluaciones económicas (EE) de América Latina. La calidad de la evidencia se valoró usando la herramienta propuesta por la colaboración Cochrane para ECAs y la escala de Newcastle-Ottawa para estudios observacionales. RESULTADOS: Se identificó dos ECAs, dos estudios observacionales y dos ETS que respondieron a la pregunta PICO de interés. No se halló RS, GPC, ni EE de países de América Latina. En comparación con solución salina, carbacol produjo menor diámetro pupilar dos minutos después de la inyección intraocular (3,2 mm vs. 4,3 mm; p<0,01), manteniendo diferencias significativas a los cinco minutos (3,1 mm vs 4,3 mm; p<0,01) y a las quince horas (3,1 vs. 4,4; p<0,01). Asimismo, produjo mejoría en la agudeza visual al primer día post-operatorio (p: 0,026), y mejores resultados en la prueba de destello moderado (p: 0,029) e intenso (p: 0,034), sin diferencias significativas a los dos meses. Los resultados en las pruebas de destello bajo, dolor ocular y defectos en el campo visual no mostraron diferencias significativas al día 1, día 7 o a los dos meses posteriores a la cirugía. La evaluación de la calidad de vida mostró diferencias significativas a favor de carbacol sobre la capacidad para descender escaleras con luz alta (81% vs. 40%; p: 0,070) o luz baja (57% vs. 25%; p: 0,037). No se observaron diferencias significativas sobre la capacidad para conducir, usar transporte público, reconocer rostros, ver televisión, o leer periódicos o etiquetas de medicamentos. CONCLUSIONES: En comparación con solución salina, carbacol produjo un efecto miótico significativamente mayor, iniciando a los dos minutos y prolongándose hasta quince horas después de la cirugía. La agudeza visual y desempeño en pruebas de destello moderado y alto en los primeros días posteriores a la cirugía fueron mejores en carbacol en comparación con solución salina, aunque similares cuando se evaluaron en puntos de tiempo más distantes al procedimiento quirúrgico. Otros desenlaces de eficacia, como pruebas de destello bajo, dolor ocular y defectos en el campo visual no mostraron diferencias significativas. Respecto a la calidad de vida, carbacol mejoró significativamente la capacidad para descender escaleras con luz alta o baja a los siete días posteriores a la cirugía, pero no mostró diferencias significativas sobre la capacidad para conducir, usar transporte público, reconocer rostros, ver televisión, o leer periódicos o etiquetas de medicamentos. En comparación con solución salina o no recibir ninguna medicación intracameral, carbacol produjo menor incidencia de sinequias anteriores periféricas a las siete semanas, sin diferencias sobre la integridad de la cámara vítrea, grosor macular central, volumen macular total, calibre de vasos retinales, ni en el grosor foveal evaluados en diferentes puntos de tiempo. Las dos ETS incluidas recomiendan el uso de carbacol intraocular durante la cirugía de catarata, a pesar de la evidencia limitada, basado en sus beneficios post-operatorios inmediatos. Los ECAs tuvieron bajo riesgo de sesgo en la mayoría de dimensiones evaluadas. Los estudios observacionales obtuvieron un puntaje de calidad de siete puntos sobre diez posibles.

Light control of G protein signaling pathways by a novel photopigment.

Channelopsins and photo-regulated ion channels make it possible to use light to control electrical activity of cells. This powerful approach has lead to a veritable explosion of applications, though it is limited to changing membrane voltage of the target cells. An enormous potential could be tapped if similar opto-genetic techniques could be extended to the control of chemical signaling pathways. Photopigments from invertebrate photoreceptors are an obvious choice-as they do not bleach upon illumination -however, their functional expression has been problematic. We exploited an unusual opsin, pScop2, recently identified in ciliary photoreceptors of scallop. Phylogenetically, it is closer to vertebrate opsins, and offers the advantage of being a bi-stable photopigment. We inserted its coding sequence and a fluorescent protein reporter into plasmid vectors and demonstrated heterologous expression in various mammalian cell lines. HEK 293 cells were selected as a heterologous system for functional analysis, because wild type cells displayed the largest currents in response to the G-protein activator, GTP-γ-S. A line of HEK cells stably transfected with pScop2 was generated; after reconstitution of the photopigment with retinal, light responses were obtained in some cells, albeit of modest amplitude. In native photoreceptors pScop2 couples to Go; HEK cells express poorly this G-protein, but have a prominent Gq/PLC pathway linked to internal Ca mobilization. To enhance pScop2 competence to tap into this pathway, we swapped its third intracellular loop-important to confer specificity of interaction between 7TMDRs and G-proteins-with that of a Gq-linked opsin which we cloned from microvillar photoreceptors present in the same retina. The chimeric construct was evaluated by a Ca fluorescence assay, and was shown to mediate a robust mobilization of internal calcium in response to illumination. The results project pScop2 as a potentially powerful optogenetic tool to control signaling pathways.

Cardiac arrest induced by muscarinic or adenosine receptors agonists is reversed by DPCPX through double mechanism.

In the right atrium (RA), adenosine and acetylcholine inhibit the pacemaker function of the sinoatrial node and induce cardiac arrest. Pre-incubation of receptor antagonists is known to inhibit the cardiac arrest induced by these agonists; however, the effect of antagonist administration after established cardiac arrest has not been described. Therefore, we assessed whether specific receptor antagonists could revert cardiac arrest induced by adenosine and muscarinic receptors activation. RA isolated from adults Wistar rats were mounted in an organ bath containing Krebs solution. Cardiac arrest was induced by adenosine or ATP (1mM), the A1 adenosine receptor agonist CPA (0.1-1µM), and muscarinic receptor agonists, carbachol (0.3-1µM) and acetylcholine (1mM). After establishing the cardiac arrest, the A1 adenosine receptor antagonist DPCPX (0.3-30µM), the muscarinic receptor antagonist atropine (10nM to 100µM) or the phosphodiesterase inhibitor IBMX (10-300µM) were incubated in order to check for the return of spontaneous contractions. DPCPX reversed the cardiac arrest induced by adenosine, ATP and CPA. In addition, atropine reversed the cardiac arrest induced by carbachol. Unexpectedly, DPCPX also reversed the cardiac arrest induced by carbachol. Similarly to DPCPX, the phosphodiesterase inhibitor IBMX reversed the cardiac arrest induced by adenosine, CPA and carbachol. The antagonism of adenosine and acetylcholine receptors activation, as well as phosphodiesterase inhibition, are able to revert cardiac arrest. DPCPX restore spontaneous contractions via the selective antagonism of A1 adenosine receptor and through a secondary mechanism likely related to phosphodiesterase inhibition.

Eficacia y seguridad del uso intraocular de carbacol 0. 01 % para la inducción de miosis intraoperatoria en cirugía de catarata / Efficacy and safety of the intraocular use of 0. 01% carbacol for the induction of intraoperative miosis in cataract surgery

La catarata es definida por la Organización Mundial de la Salud (OMS) como la opacificación del lente cristalino que generalmente ocurre por el envejecimiento, trauma, o alguna enfermedad sistémica, afectando la capacidad visual de la persona. Esta disminución de la capacidad visual o incluso la ceguera, es un problema de salud pública en adultos y adultos mayores. En el Perú, aproximadamente el 0.6 % de la población tiene ceguera, cuya causa en el 47 % de los casos son por las cataratas. El tratamiento indicado para la catarata es la intervención quirúrgica, la cual consiste en reemplazar el cristalino opacificado o catarata por un lente intraocular. Hay dos formas de realizar esto, mediante la extracción extracapsular del cristalino opacificado, o mediante la facoemulsificación del cristalino, que consiste en un proceso de destrucción mediante ondas vibratorias ultrasónicas. Luego de ello, se realiza la implantación de un nuevo lente intraocular con soporte capsular, el cual reemplaza al cristalino permitiendo que el paciente vuelva tener una visión adecuada. Posterior a la implantación del lente intraocular se realiza la inducción de miosis pupilar para mantener el lente dentro de la bolsa capsular, evitar la captura del lente por el iris y el prolapso del iris por las heridas operatorias. La inducción de miosis luego de una intervención por catarata debe realizarse inmediatamente después de la implantación del lente, por lo que la vía de administración indicada es la inyección intraocular del agente miótico. De este modo, se espera que el efecto miótico se prolongue hasta por 24 horas, mientras que la aplicación tópica de un agente miótico se limita a un efecto que bordea las ocho horas, y sólo se puede realizar en el periodo postoperatorio, por lo que se genera un periodo entre la intervención quirúrgica y la aplicación del agente miótico que expone al paciente a las potenciales complicaciones anteriormente mencionadas. Aunque algunos estudios de serie de casos clínicos indican el uso de pilocarpina 2 %, el cual se encuentra disponible en el Petitorio Farmacológico de EsSalud, este medicamento no ha sido aprobado por la FDA para uso intraocular, sólo para uso tópico, dado que su uso intraocular puede ser tóxico o incrementar el riesgo de infecciones intraoculares. Así, en la actualidad EsSalud no cuenta con un medicamento miótico de uso intraocular autorizado, por lo cual, surge la necesidad de evaluar otras alternativas que pudieran ser de beneficio para dichos pacientes. OBJETIVO: objetivo del presente dictamen fue evaluar la eficacia y seguridad del uso intraocular de carbacol 0.01 % para la inducción de miosis intraoperatoria en las intervenciones quirúrgicas por catarata. Carbacol es um colinérgico o parasimpaticomimético potente, que actúa como agonista del receptor de acetilcolina, inhibiendo la acetilcolinesterasa y estimulando tanto los receptores muscarínicos como nicotínicos, produciendo miosis a través de la constricción del iris y del cuerpo ciliar, y reduciendo la presión intraocular. TECNOLOGÍA SANITARIA DE INTERÉS: CARBACOL. Carbacol, también conocido como carbamilcolina, es un colinérgico o parasimpaticomimético potente, que actúa como agonista del receptor de acetilcolina, inhibiendo la acetilcolinesterasa y estimulando tanto los receptores muscarínicos como nicotínicos, produciendo constricción del iris y del cuerpo ciliar y además reduciendo la presión intraocular. El agente colinérgico fue aprobado por la Administración de Drogas y Alimentos (FDA, por sus siglas en inglés) en el año 2002 (FDA, 2015). METODOLOGÍA: Se realizó una búsqueda sin restricción de idioma hasta mayo del 2018. La formulación de la estrategia de búsqueda incluyó los criterios de elegibilidad, los términos controlados propios de cada base y términos libres. Asimismo, se buscaron otros documentos potencialmente elegibles a través de la revisión del listado de referencias de los documentos seleccionados para lectura a texto completo. Por último, la selección de la evidencia siguió el flujograma mostrado en la subsección de resultados. RESULTADOS: Luego de la búsqueda sistemática realizada, se identificaron dos ensayos clínicos aleatorizados (ECA) Beasley, 1972 y Solomon et al., 1998; y el estudio de serie de casos de Pekel et al., 2014. Si bien estos estudios muestran algunas limitaciones que serán analizadas más adelante, es la evidencia de mayor relevancia en torno al uso de carbacol para la inducción de miosis intraoperatoria en las intervenciones quirúrgicas por catarata. Con respecto a la eficacia de carbacol en la inducción de miosis, el estudio de Beasley, 1972 muestra que el efecto miótico a los dos minutos de la inyección intraocular es significativamente mayor en carbacol, con respecto a placebo (p<0.01) y que el efecto miótico persiste por lo menos por 15 horas. Por otro lado, a la séptima semana postoperatoria, se observó una incidencia significativamente menor de sinequias anteriores periféricas (SAP) en el grupo que recibió carbacol (11 %), en comparación al grupo que recibió a placebo (35 %). Al analizar el impacto sobre la calidad de vida por parte de carbacol mediante el cuestionario modificado de SF-36, el cual mide la percepción del paciente sobre su estado de salud, el estudio de Solomon et al., 1998 muestra que carbacol incrementa la agudeza visual durante el primer día postoperatorio, con respecto a placebo, y muestra una diferencia estadísticamente significativa en el porcentaje de sujetos que pueden descender las escaleras sin ayuda durante la primera semana posterior a la intervención quirúrgica, tanto en un ambiente con luz brillante (p=0.007) o con luz tenue (p=0.037), siendo un potencial factor protector en pacientes con riesgo de presentar caídas acci Con respecto a los eventos adversos, los estudios evaluados no encontraron casos de inflamación intraocular ni de cefalea frontal. El estudio Pekel et al., 2015 muestra que sólo en el primer día postoperatorio hubo un menor volumen macular total (VMD y del grosor macular central (GMC) con respecto al volumen preoperatorio. Mientras que, durante el seguimiento (al primer día, a la primera semana y al primer mes) no se encontraron diferencias estadísticamente significativas en la presencia de edema macular, ni en el calibre de los vasos retinianos (CVR) al comparar los pacientes que recibieron carbacol con los que no lo recibieron. dentales y fractura de caderas. CONCLUSIONES: El presente dictamen preliminar muestra la evidencia disponible hasta mayo 2018 con respecto al uso intraocular de carbacol 0.01 % en comparación con placebo para la inducción de miosis intraoperatoria en pacientes operados de cataratas. No se encontraron guías de práctica clínica, revisiones sistemáticas ni evaluaciones de tecnologías sanitarias que respondan la pregunta PICO de la presente evaluación. Finalmente, se identificaron dos ECA y un estudio de serie de casos como sustento para la elaboración del presente dictamen preliminar. Al evaluar la eficacia de carbacol en la inducción de miosis, el estudio Beasley, 1972 muestra que carbacol genera miosis dentro de los dos minutos de ser aplicado y que su efecto perdura por más de 15 horas. Esto se traduce en una menor incidencia de SAP a la sétima semana postoperatorio, con respecto a placebo. Aunque no se aprecia diferencia en la conservación de la integridad de la cámara vítrea. Con respecto a los eventos adversos, los estudios evaluados no observaron casos de inflamación intraocular ni de cefalea frontal, mientras que el estudio Pekel et al., 2015 muestra que carbacol disminuye el volumen macular total (VMT) y el grosor macular central (GMT) en el primer día postoperatorio, mas no en la primera semana, ni primer mes. Por otro lado, no se ve afectado el calibre de los vasos retinianos (CVR). Estos resultados muestran una cierta protección ante el edema macular en el postoperatorio inmediato y ausencia de secuelas en la morfología macular, sin embargo, se debe tener en cuenta el posible sesgo de medición que conlleva. En resumen, carbacol es un agente miótico que inicia su acción dentro de los dos minutos de su inyección, manteniendo su efecto por más de 15 horas, generando un beneficio en el periodo postoperatorio inmediato en la agudeza visual y en el volumen macular total. Asimismo, los estudios no reportan eventos adversos como edema macular, cefalea, y, por el contrario, refieren una reducción en la incidencia de SAP, mas no hay una diferencia en la preservación de la integridad de la cámara vítrea, al ser comparado con placebo. Con respecto a la calidad de vida en el postoperatorio, se observa un inicio más temprano de la deambulación y autonomía en el uso de las escaleras, lo que podría tener un impacto positivo en el estilo de vida de los pacientes intervenidos. Por lo expuesto, el Instituto de Evaluaciones de Tecnologías en Salud e Investigación - IETSI aprueba el uso de carbacol, según lo establecido en el Anexo N.° 1. La vigencia del presente dictamen preliminar es de dos años a partir de la fecha de publicación.

Eficacia y seguridad del uso intraocular de carbacol 0. 01 % para la inducción de miosis intraoperatoria en cirugía de catarata / Eficácia e segurança do uso intra-ocular de carbacol 0, 01% para indução de miosite intra-operatória em cirurgia de catarata

INTRODUCCIÓN: El presente dictamen preliminar expone la evaluación de tecnología de la eficacia y seguridad del uso intraocular de carbacol 0.01% para la inducción de miosis intraoperatoria en pacientes operados de cataratas. La catarata es definida por la Organización Mundial de la Salud (OMS) como la opacificación del lente cristalino que generalmente ocurre por el envejecimiento, trauma, o alguna enfermedad sistémica, afectando la capacidad visual de la persona. Esta disminución de la capacidad visual o incluso la ceguera, es un problema de salud pública en adultos y adultos mayores. En el Perú, aproximadamente el 0.6 % de la población tiene ceguera, cuya causa en el 47 % de los casos son por las cataratas. El tratamiento indicado para la catarata es la intervención quirúrgica, la cual consiste en reemplazar el cristalino opacificado o catarata por un lente intraocular. Hay dos formas de realizar esto, mediante la extracción extracapsular del cristalino opacificado, o mediante la facoemulsificación del cristalino, que consiste en un proceso de destrucción mediante ondas vibratorias ultrasónicas. Luego de ello, se realiza la implantación de un nuevo lente intraocular con soporte capsular, el cual reemplaza al cristalino permitiendo que el paciente vuelva tener una visión adecuada. Posterior a la implantación del lente intraocular se realiza la inducción de miosis pupilar para mantener el lente dentro de la bolsa capsular, evitar la captura del lente por el iris y el prolapso del iris por las heridas operatorias. TECNOLOGÍA SANITARIA DE INTERÉS: Carbacol, también conocido como carbamilcolina, es un colinérgico o parasimpaticomimético potente, que actúa como agonista del receptor de acetilcolina, inhibiendo la acetilcolinesterasa y estimulando tanto los receptores muscarínicos como nicotínicos, produciendo constricción del iris y del cuerpo ciliar y además reduciendo la presión intraocular. METODOLOGÍA: Se realizó una búsqueda sin restricción de idioma hasta mayo del 2018. La formulación de la estrategia de búsqueda incluyó los criterios de elegibilidad, los términos controlados propios de cada base y términos libres. Asimismo, se buscaron otros documentos potencialmente elegibles a través de la revisión del listado de referencias de los documentos seleccionados para lectura a texto completo. Por último, la selección de la evidencia siguió el flujograma mostrado en la subsección de resultados. RESULTADOS: Luego de la búsqueda sistemática realizada, se identificaron dos ensayos clínicos aleatorizados (ECA) Beasley, 1972 y Solomon et al., 1998; y el estudio de serie de casos de Pekel et al., 2014. Si bien estos estudios muestran algunas limitaciones que serán analizadas más adelante, es la evidencia de mayor relevancia en torno al uso de carbacol para la inducción de miosis intraoperatoria en las intervenciones quirúrgicas por catarata. CONCLUSIONES: El presente dictamen preliminar muestra la evidencia disponible hasta mayo 2018 con respecto al uso intraocular de carbacol 0.01 % en comparación con placebo para la inducción de miosis intraoperatoria en pacientes operados de cataratas. No se encontraron guías de práctica clínica, revisiones sistemáticas ni evaluaciones de tecnologías sanitarias que respondan la pregunta PICO de la presente evaluación. Finalmente, se identificaron dos ECA y un estudio de serie de casos como sustento para la elaboración del presente dictamen preliminar. Al evaluar la eficacia de carbacol en la inducción de miosis, el estudio Beasley, 1972 muestra que carbacol genera miosis dentro de los dos minutos de ser aplicado y que su efecto perdura por más de 15 horas. Esto se traduce en una menor incidencia de SAP a la sétima semana postoperatorio, con respecto a placebo. Aunque no se aprecia diferencia en la conservación de la integridad de la cámara vítrea. Con respecto a los eventos adversos, los estudios evaluados no observaron casos de inflamación intraocular ni de cefalea frontal, mientras que el estudio Pekel et al., 2015 muestra que carbacol disminuye el volumen macular total (VMT) y el grosor macular central (GMT) en el primer día postoperatorio, mas no en la primera semana, ni primer mes. Por otro lado, no se ve afectado el calibre de los vasos retinianos (CVR). Estos resultados muestran una cierta protección ante el edema macular en el postoperatorio inmediato y ausencia de secuelas en la morfología macular, sin embargo, se debe tener en cuenta el posible sesgo de medición que conlleva. El Instituto de Evaluaciones de Tecnologías en Salud e Investigación ­ IETSI aprueba el uso de carbacol. La vigencia del presente dictamen preliminar es de dos años a partir de la fecha de publicación.

Extracellular acidosis selectively inhibits pharmacomechanical coupling induced by carbachol in strips of rat gastric fundus.

NEW FINDINGS: What is the central question of this study? Acute acidosis that results from short-term exercise is involved in delayed gastric emptying in rats and the lower responsiveness of gastric fundus strips to carbachol. Does extracellular acidosis decrease responsiveness to carbachol in tissues of sedentary rats? How? What is the main finding and its importance? Extracellular acidosis inhibits cholinergic signalling in the rat gastric fundus by selectively influencing the Gq/11 protein signalling pathway. Acute acidosis that results from short-term exercise delays gastric emptying in rats and decreases the responsiveness to carbachol in gastric fundus strips. The regulation of cytosolic Ca2+ concentrations appears to be a mechanism of action of acidosis. The present study investigated the way in which acidosis interferes with gastric smooth muscle contractions. Rat gastric fundus isolated strips at pH 6.0 presented a lower magnitude of carbachol-induced contractions compared with preparations at pH 7.4. This lower magnitude was absent in carbachol-stimulated duodenum and KCl-stimulated gastric fundus strips. In Ca2+ -free conditions, repeated contractions that were induced by carbachol progressively decreased, with no influence of extracellular pH. In fundus strips, CaCl2 -induced contractions were lower at pH 6.0 than at pH 7.4 but only when stimulated in the combined presence of carbachol and verapamil. In contrast, verapamil-sensitive contractions that were induced by CaCl2 in the presence of KCl did not change with pH acidification. In Ca2+ store-depleted preparations that were treated with thapsigargin, the contractions that were induced by extracellular Ca2+ restoration were smaller at pH 6.0 than at pH 7.4, but relaxation that was induced by SKF-96365 (an inhibitor of store-operated Ca2+ entry) was unaltered by extracellular acidification. At pH 6.0, the phospholipase C inhibitor U-73122 relaxed carbachol-induced contractions less than at pH 7.4, and this phenomenon was absent in tissue that was treated with the RhoA kinase blocker Y-27632. Thus, extracellular acidosis inhibited pharmacomechanical coupling in gastric fundus by selectively inhibiting the Gq/11 protein signalling pathway, whereas electromechanical coupling remained functionally preserved.

Cholinergic/opioid interaction in anterior cingulate cortex reduces the nociceptive response of vocalization in guinea pigs.

The anterior cingulate cortex (ACC) is crucial in the modulation of the sensory, affective and cognitive aspects of nociceptive processing. Also, it participates in the planning and execution of behavioral responses evoked by nociceptive stimuli via descending projections to the brainstem. In laboratory animals nociceptive experimental tests evaluate behavioral responses that preferentially express the sensory-discriminative or affective-motivational component of pain. The objective of this study was to investigate the participation of opioid and cholinergic neurotransmission in the ACC on different nociceptive responses in guinea pigs. We used nociceptive tests of formalin and vocalization evoked by peripheral noxious stimuli (electric shock) to evaluate the behavioral expression of the sensory-discriminative and affective motivational components, respectively. We verified that the microinjection of morphine (4.4nmol) in the ACC of guinea pigs promotes antinociception in the two experimental tests investigated. This effect is blocked by prior microinjection of naloxone (2.7nmol). On the other hand, the microinjection of carbachol (2.7nmol) in the ACC induces antinociception only in the vocalization test. This effect was prevented by prior microinjection of atropine (0.7nmol) and naloxone (2.7nmol). In fact, the blockade of µ-opioids receptors with naloxone in ACC prevented the antinociceptive effect of carbachol in the vocalization test. Accordingly, we suggest that the antinociception promoted by carbachol was mediated by the activation of muscarinic receptors on local ACC opioid interneurons. The release of endogenous opioids seems to inhibited the expression of the behavioral response of vocalization. Therefore, we verified that the antinociceptive effect of morphine microinjection in ACC is broader and more robust than that promoted by carbachol.