RESUMEN
The arcuate nucleus of hypothalamus (ARC) integrates circulating factors that signal energy status. The vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) are widely distributed in the periphery and central nervous systems (CNS) and play important roles on energy balance. The present study aimed to investigate the responses of microinjection of VIP and PACAP in the ARC on metabolic changes and food intake. In addition, the activity of neurons in the ARC following intracerebroventricular (ICV) microinjection of these peptides was also evaluated. Microinjection of VIP or PACAP in the ARC decreased fasting-induced hyperphagia and food intake, decreased total lipids, and increased free fatty acids plasma concentrations. VIP microinjection in the ARC induced hyperglycemia and decreased total cholesterol level; and PACAP reduced triglycerides concentration. ICV microinjection of VIP and PACAP enhanced neuronal activation in the ARC, associated with lower fasting-induced hyperphagia and plasma metabolic changes (only VIP). These results suggest that VIP and PACAP play important roles in ARC, inducing hypophagia and peripheral metabolic changes, as hyperglycemia, increased free fatty acids and decreased total lipids plasma levels.
Asunto(s)
Núcleo Arqueado del Hipotálamo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa , Péptido Intestinal Vasoactivo , Animales , Núcleo Arqueado del Hipotálamo/metabolismo , Conducta Alimentaria , Hipotálamo/metabolismo , Lípidos/sangre , Neuronas/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Péptido Intestinal Vasoactivo/metabolismo , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
Hypothalamic kisspeptin neurons are the primary modulators of gonadotropin-releasing hormone (GnRH) neurons. It has been shown that circadian rhythms driven by the suprachiasmatic nucleus (SCN) contribute to GnRH secretion. Kisspeptin neurons are potential targets of SCN neurons due to reciprocal connections with the anteroventral periventricular and rostral periventricular nuclei (AVPV/PeN) and the arcuate nucleus of the hypothalamus (ARH). Vasoactive intestinal peptide (VIP), a notable SCN neurotransmitter, modulates GnRH secretion depending on serum estradiol levels, aging or time of the day. Considering that kisspeptin neurons may act as interneurons and mediate VIP's effects on the reproductive axis, we investigated the effects of VIP on hypothalamic kisspeptin neurons in female mice during estrogen negative feedback. Our findings indicate that VIP induces a TTX-independent depolarization of approximately 30% of AVPV/PeN kisspeptin neurons in gonad-intact (diestrus) and ovariectomized (OVX) mice. In the ARH, the percentage of kisspeptin neurons that were depolarized by VIP was even higher (approximately 90%). An intracerebroventricular infusion of VIP leds to an increased percentage of kisspeptin neurons expressing the phosphoSer133 cAMP-response-element-binding protein (pCREB) in the AVPV/PeN. On the other hand, pCREB expression in ARH kisspeptin neurons was similar between saline- and VIP-injected mice. Thus, VIP can recruit different signaling pathways to modulate AVPV/PeN or ARH kisspeptin neurons, resulting in distinct cellular responses. The expression of VIP receptors (VPACR) was upregulated in the AVPV/PeN, but not in the ARH, of OVX mice compared to mice on diestrus and estradiol-primed OVX mice. Our findings indicate that VIP directly influences distinct cellular aspects of the AVPV/PeN and ARH kisspeptin neurons during estrogen negative feedback, possibly to influence pulsatile LH secretion.
Asunto(s)
Kisspeptinas , Péptido Intestinal Vasoactivo , Animales , Estradiol/metabolismo , Estradiol/farmacología , Estrógenos/metabolismo , Estrógenos/farmacología , Retroalimentación , Femenino , Hormona Liberadora de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Ratones , Neuronas/metabolismo , Péptido Intestinal Vasoactivo/metabolismo , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
BACKGROUND: The synaptic vesicle glycoprotein 2 (SV2) family is essential to the synaptic machinery involved in neurotransmission and vesicle recycling. The isoforms SV2A, SV2B and SV2C are implicated in neurological diseases such as epilepsy, Alzheimer's and Parkinson's disease. Suitable cell systems for studying regulation of these proteins are essential. Here we present gene expression data of SV2A, SV2B and SV2C in two human neuroblastoma cell lines after differentiation. METHODS: Human neuroblastoma cell lines SiMa and IMR-32 were treated for seven days with growth supplements (B-27 and N-2), all-trans-retinoic acid (ATRA) or vasoactive intestinal peptide (VIP) and gene expression levels of SV2 and neuronal targets were analyzed. RESULTS: The two cell lines reacted differently to the treatments, and only one of the three SV2 isoforms was affected at a time. SV2B and choline O-acetyltransferase (CHAT) expression was changed in concert after growth supplement treatment, decreasing in SiMa cells while increasing in IMR-32. ATRA treatment resulted in no detected changes in SV2 expression in either cell line while VIP increased both SV2C and dopamine transporter (DAT) in IMR-32 cells. CONCLUSION: The synergistic expression patterns between SV2B and CHAT as well as between SV2C and DAT mirror the connectivity between these targets found in disease models and knock-out animals, although here no genetic alteration was made. These cell lines and differentiation treatments could possibly be used to study SV2 regulation and function.
Asunto(s)
Diferenciación Celular/genética , Regulación Neoplásica de la Expresión Génica , Glicoproteínas de Membrana/genética , Proteínas del Tejido Nervioso/genética , Neuroblastoma/genética , Neuroblastoma/patología , Sitios de Unión , Diferenciación Celular/efectos de los fármacos , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Glicoproteínas de Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Regiones Promotoras Genéticas/genética , Factores de Transcripción/metabolismo , Sitio de Iniciación de la Transcripción , Tretinoina/farmacología , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
BACKGROUND: Lupus nephritis (LN) is an inflammation of the kidneys and is a major cause of mortality in systemic lupus erythaematosus (SLE) patients. In addition, Th17/Treg balance is one of the most important factors that can promote the development of LN. It has been reported that vasoactive intestinal peptide (VIP) is associated with the downregulation of both inflammatory and autoimmune diseases through regulating T lymphocyte balance. Therefore, the aim of this study was to determine the role of VIP in modulating Th17/Treg balance in LN. METHODS: LN was induced in BALB/c female mice by injection pristane. After 3 months, mice were randomly divided into four groups: control, VIP + control, LN and VIP + LN. Autoantibody levels were tested by ELISA. The distribution of Th17/Treg cells in vivo and in vitro was detected by FC. Renal tissues were examined by PASM and DIF for pathology and Foxp3+CD3+. The mRNA and protein expression levels of pro- and anti-inflammatory cytokines were detected by qRT-PCR and western blotting. RESULTS: VIP can improve renal injury by regulating Th17/Treg imbalance in LN mice. Proteinuria, renal function defects and autoantibodies were significantly decreased, and Th17/Treg cell balance was restored in VIP compared with LN mice. In addition, VIP improved renal lesions by promoting the expression of Foxp3+CD3+ in renal tissue. Furthermore, VIP downregulated the mRNA and protein expression of IL-17, IL-6 and upregulated Foxp3, IL-10 expression. CONCLUSIONS: VIP reduced LN proteinuria and renal function defects and restored the Th17/Treg cell balance. Furthermore, VIP also downregulated autoantibody and inflammatory cytokine expression and upregulated Foxp3 and IL-10 expression.
Asunto(s)
Nefritis Lúpica/sangre , Nefritis Lúpica/tratamiento farmacológico , Linfocitos T Reguladores/metabolismo , Terpenos/toxicidad , Células Th17/metabolismo , Péptido Intestinal Vasoactivo/uso terapéutico , Animales , Modelos Animales de Enfermedad , Femenino , Nefritis Lúpica/inducido químicamente , Ratones , Ratones Endogámicos BALB C , Linfocitos T Reguladores/efectos de los fármacos , Células Th17/efectos de los fármacos , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
Asthma is a chronic respiratory disease characterized by airway inflammation, bronchoconstriction, airway hyperresponsiveness and recurring attacks of impaired breathing. Vasoactive intestinal peptide (VIP) has been proposed as a novel anti-asthma drug due to its effects on airway smooth muscle relaxation, bronchodilation and vasodilation along with its immunomodulatory and anti-inflammatory properties. In the current study, we investigated the therapeutic effects of VIP when conjugated with α-alumina nanoparticle (α-AN) to prevent enzymatic degradation of VIP in the respiratory tract. VIP was conjugated with α-AN. Balb/c mice were sensitized and challenges with ovalbumin (OVA) or PBS and were divided in four groups; VIP-treated, α-AN-treated, α-AN-VIP-treated and beclomethasone-treated as a positive control group. Specific and total IgE level, airway hyperresponsiveness (AHR), bronchial cytokine expression and lung histology were measured. α-AN-VIP significantly reduced the number of eosinophils (Eos), serum IgE level, Th2 cytokines and AHR. These effects of α-AN-VIP were more pronounced than that seen with beclomethasone or VIP alone (P<0.05). The current data indicate that α-AN-VIP can be considered as an effective nano-drug for the treatment of asthma.
Asunto(s)
Óxido de Aluminio/química , Antiasmáticos/química , Antiasmáticos/farmacología , Asma/tratamiento farmacológico , Nanopartículas/química , Péptido Intestinal Vasoactivo/química , Péptido Intestinal Vasoactivo/farmacología , Animales , Antiasmáticos/uso terapéutico , Asma/sangre , Asma/complicaciones , Asma/inmunología , Portadores de Fármacos/química , Estabilidad de Medicamentos , Eosinofilia/complicaciones , Femenino , Inmunoglobulina E/sangre , Pulmón/efectos de los fármacos , Pulmón/inmunología , Pulmón/patología , Ratones , Péptido Intestinal Vasoactivo/uso terapéuticoRESUMEN
Avian prolactin (PRL) secretion is under stimulatory control by the PRL-releasing factor (PRF), vasoactive intestinal peptide (VIP). The neuroendocrine regulation of the avian reproductive system has been extensively studied in females. However, there are limited data in males. The aim of this study was to elucidate the VIPergic system and its relationship to PRL and testosterone (T) in the male native Thai chicken. The distributions of VIP-immunoreactive (-ir) neurons and fibers were determined by immunohistochemistry. Changes in VIP-ir neurons within the nucleus inferioris hypothalami (IH) and nucleus infundibuli hypothalami (IN) areas were compared across the reproductive stages. Plasma levels of PRL and T were determined by enzyme-linked immunosorbent assay and then compared across the reproductive stages. The results revealed that the highest accumulations of VIP-ir neurons were concentrated only within the IH-IN, and VIP-ir neurons were not detected within other hypothalamic nuclei. Within the IH-IN, VIP-ir neurons were low in premature and aging males and markedly increased in mature males. Changes in VIP-ir neurons within the IH-IN were directly mirrored with changes in PRL and T levels across the reproductive stages. These results suggested that VIP neurons in the IH-IN play a regulatory role in year-round reproductive activity in males. The present study also provides additional evidence that VIP is the PRF in non-seasonal, continuously breeding equatorial species.
Asunto(s)
Pollos/anatomía & histología , Hipotálamo/citología , Neuronas/efectos de los fármacos , Péptido Intestinal Vasoactivo/farmacología , Animales , Pollos/sangre , Pollos/fisiología , Femenino , Inmunohistoquímica , Masculino , Neuronas/clasificación , Prolactina/sangre , Prolactina/metabolismo , Testosterona/sangre , Testosterona/metabolismoRESUMEN
The objective of this study was to investigate the effects of 2% L-glutamine supplementation on myenteric innervation in the ileum of diabetic rats, grouped as follows: normoglycemic (N); normoglycemic supplemented with L-glutamine (NG); diabetic (D); and diabetic supplemented with L-glutamine (DG). The ileums were subjected to immunohistochemical techniques to localize neurons immunoreactive to HuC/D protein (HuC/D-IR) and neuronal nitric oxide synthase enzyme (nNOS-IR) and to analyze varicosities immunoreactive to vasoactive intestinal polypeptide (VIP-IR) and calcitonin gene-related peptide (CGRP-IR). L-Glutamine in the DG group (i) prevented the increase in the cell body area of nNOS-IR neurons, (ii) prevented the increase in the area of VIP-IR varicosities, (iii) did not prevent the loss of HuC/D-IR and nNOS-IR neurons per ganglion, and (iv) reduced the size of CGRP-IR varicosities. L-Glutamine in the NG group reduced (i) the number of HuC/D-IR and nNOS-IR neurons per ganglion, (ii) the cell body area of nNOS-IR neurons, and (iii) the size of VIP-IR and CGRP-IR varicosities. 2% L-glutamine supplementation exerted differential neuroprotective effects in experimental diabetes neuropathy that depended on the type of neurotransmitter analyzed. However, the effects of this dose of L-glutamine on normoglycemic animals suggests there are additional actions of this beyond its antioxidant capacity.
Asunto(s)
Diabetes Mellitus Experimental , Glutamina/farmacología , Íleon/inervación , Plexo Mientérico/efectos de los fármacos , Animales , Péptido Relacionado con Gen de Calcitonina/farmacología , Cuerpo Celular/efectos de los fármacos , Glutamina/administración & dosificación , Inmunohistoquímica , Neuronas/efectos de los fármacos , Neuronas Nitrérgicas , Óxido Nítrico Sintasa de Tipo I/farmacología , Ratas , Ratas Wistar , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
BACKGROUND: Breakdown of the intestinal barrier is a driving force of sepsis and multiple organ failure. Radical scavengers or cytokine inhibitors may have a therapeutic impact on intestinal failure. Therapeutic effects on different sites of small intestine and colon have not been compared. Therefore, we investigated time-dependent intestinal permeability changes and their therapeutic inhibition in colon and small intestine with an ex vivo model. METHODS: Male Sprague-Dawley rats were either pretreated for 24 h with lipopolysaccharide (LPS) intraperitoneally alone or in combination with a radical scavenger (pyruvate or Tempol) or a cytokine inhibitor (parecoxib or vasoactive intestinal peptide). The gastrointestinal permeability was measured by time-dependent fluorescein isothiocyanate inulin diffusion using washed and everted tube-like gut segments. Blood and tissue samples were taken to investigate the development of inflammatory cytokine level (interleukin 6) in the context of cytokine inhibition and reactive oxygen species level via nicotinamide adenine dinucleotide phosphate oxidase activity in radical scavenger groups. RESULTS: After LPS treatment, mucosal permeability was enhanced up to 170% in small intestine and colon. In the small intestine the most significant reduction in permeability was found for pyruvate and parecoxib. Treatment with vasoactive intestinal peptide and parecoxib resulted in the most pronounced reduction of permeability in the colon. CONCLUSIONS: Our data suggest that cytokine inhibitors and radical scavengers have pronounced effects in LPS-induced disrupted intestinal barrier of the colon and small intestine. Our novel model comparing different anatomic sites and different points in time after the onset of sepsis may contribute to gain new insight into mechanisms and treatment options of sepsis-related gut mucosal breakdown.
Asunto(s)
Inhibidores de la Ciclooxigenasa 2/uso terapéutico , Depuradores de Radicales Libres/uso terapéutico , Mucosa Intestinal/efectos de los fármacos , Insuficiencia Multiorgánica/prevención & control , Péptido Intestinal Vasoactivo/uso terapéutico , Animales , Óxidos N-Cíclicos/farmacología , Óxidos N-Cíclicos/uso terapéutico , Inhibidores de la Ciclooxigenasa 2/farmacología , Evaluación Preclínica de Medicamentos , Depuradores de Radicales Libres/farmacología , Interleucina-6/sangre , Isoxazoles/farmacología , Isoxazoles/uso terapéutico , Lipopolisacáridos , Masculino , Insuficiencia Multiorgánica/etiología , NADPH Oxidasas/metabolismo , Neutrófilos/enzimología , Permeabilidad/efectos de los fármacos , Ácido Pirúvico/farmacología , Ácido Pirúvico/uso terapéutico , Ratas Sprague-Dawley , Sepsis/complicaciones , Marcadores de Spin , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
We have earlier shown that PACAP-38 decreases neurogenic inflammation. However, there were no data on its receptorial mechanism and the involvement of its PAC1 and VPAC1/2 receptors (PAC1R, VPAC1/2R) in this inhibitory effect. Neurogenic inflammation in the mouse ear was induced by topical application of the Transient Receptor Potential Ankyrin 1 (TRPA1) receptor activator mustard oil (MO). Consequent neurogenic edema, vasodilation and plasma leakage were assessed by measuring ear thickness with engineer's micrometer, detecting tissue perfusion by laser Doppler scanning and Evans blue or indocyanine green extravasation by intravital videomicroscopy or fluorescence imaging, respectively. Myeloperoxidase activity, an indicator of neutrophil infiltration, was measured from the ear homogenates with spectrophotometry. The selective PAC1R agonist maxadilan, the VPAC1/2R agonist vasoactive intestinal polypeptide (VIP) or the vehicle were administered i.p. 15 min before MO. Substance P (SP) concentration of the ear was assessed by radioimmunoassay. Maxadilan significantly diminished MO-induced neurogenic edema, increase of vascular permeability and vasodilation. These inhibitory effects of maxadilan may be partially due to the decreased substance P (SP) levels. In contrast, inhibitory effect of VIP on ear swelling was moderate, without any effect on MO-induced plasma leakage or SP release, however, activation of VPAC1/2R inhibited the increased microcirculation caused by the early arteriolar vasodilation. Neither the PAC1R, nor the VPAC1/2R agonist influenced the MO-evoked increase in tissue myeloperoxidase activity. These results clearly show that PAC1R activation inhibits acute neurogenic arterial vasodilation and plasma protein leakage from the venules, while VPAC1/2R stimulation is only involved in the attenuation of vasodilation.
Asunto(s)
Proteínas de Insectos/farmacología , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/agonistas , Fenómenos Fisiológicos de la Piel/efectos de los fármacos , Vasoconstrictores/farmacología , Vasodilatación/efectos de los fármacos , Animales , Permeabilidad Capilar/efectos de los fármacos , Permeabilidad Capilar/fisiología , Modelos Animales de Enfermedad , Oído/patología , Oído/fisiopatología , Edema , Femenino , Masculino , Ratones , Microcirculación/efectos de los fármacos , Microcirculación/fisiología , Planta de la Mostaza , Peroxidasa/metabolismo , Aceites de Plantas , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/metabolismo , Receptores de Tipo II del Péptido Intestinal Vasoactivo/agonistas , Receptores de Tipo II del Péptido Intestinal Vasoactivo/metabolismo , Receptores de Tipo I del Polipéptido Intestinal Vasoactivo/agonistas , Receptores de Tipo I del Polipéptido Intestinal Vasoactivo/metabolismo , Sustancia P/metabolismo , Péptido Intestinal Vasoactivo/farmacología , Vasodilatación/fisiologíaRESUMEN
Mesenteric lymph pathway serves as the primary route by which gut injury leads to systemic inflammation and distant organ injury. The inflammation of the intestinal tract is partially mediated by vasoactive intestinal peptide (VIP). Therefore, the aim of this study was to test whether exogenous VIP affects mesenteric lymph pathway during early intestinal ischemia-reperfusion (IIR) injury. Rats were randomized into control, control+VIP, IIR and IIR+VIP groups. The observation of mesenteric lymph flow was carried out by cannulation of mesenteric lymphatics. The distribution of in vivo lymphocyte trafficking was performed by (51)Cr labeled lymphocytes and was measured by γ-counter. Endotoxin concentration was assayed using the limulus test kit and TNF-α level was detected by ELISA. When IIR injury treated with VIP, the volumes of lymph flow increased by 80%, which caused the number of lymphocytes exiting in mesenteric lymphatic increased by 50% while the proportion of (51)Cr-lymphocytes in Peyer's patches, intestinal effector tissues, mesenteric nodes, large intestine, stomach decreased by 58%, 51%, 58%, 63%, 64% respectively at the 6th h after reperfusion following intestinal ischemia. Meanwhile, endotoxin and TNF-α levels in intestinal lymph decreased by 51% and 83%. These results suggest that exogenous VIP ameliorates IIR induced splanchnic organ damage via inhibition of toxic mediators reaching systemic circulation and reinforcement of the effective immune responses in gut-associated lymphoid tissues (GALT).
Asunto(s)
Íleon/inmunología , Oclusión Vascular Mesentérica/inmunología , Daño por Reperfusión/inmunología , Péptido Intestinal Vasoactivo/farmacología , Animales , Movimiento Celular , Evaluación Preclínica de Medicamentos , Endotoxinas/sangre , Íleon/irrigación sanguínea , Íleon/efectos de los fármacos , Íleon/metabolismo , Linfa/inmunología , Vasos Linfáticos/fisiopatología , Recuento de Linfocitos , Linfocitos/inmunología , Linfocitos/fisiología , Masculino , Arterias Mesentéricas/fisiopatología , Oclusión Vascular Mesentérica/tratamiento farmacológico , Oclusión Vascular Mesentérica/metabolismo , Oclusión Vascular Mesentérica/patología , Ratas , Ratas Wistar , Daño por Reperfusión/tratamiento farmacológico , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Factor de Necrosis Tumoral alfa/sangre , Péptido Intestinal Vasoactivo/fisiologíaRESUMEN
PURPOSE: To determine the intracellular signaling pathways that vasoactive intestinal peptide (VIP) uses to stimulate high molecular weight glycoconjugate secretion from cultured rat conjunctival goblet cells. METHODS: Goblet cells from rat bulbar and forniceal conjunctiva were grown in organ culture. Presence and localization of VIP receptors (VPAC1 and 2) were determined by RT-PCR, immunofluorescence microscopy and Western blot analysis. Intracellular [Ca(2+)] ([Ca(2+)]i) was measured using fura-2. Extracellular signal-regulated kinase (ERK)-1/2 activity was determined by Western blot analysis. High molecular weight glycoconjugate secretion was measured with an enzyme-linked lectin assay on cultured goblet cells that were serum-starved for 2 hours before stimulation with VIP, VPAC1-, or VPAC2-specific agonists. Inhibitors were added 30 minutes prior to VIP. Activation of epidermal growth factor receptor (EGFR) was measured by immunoprecipitation using an antibody against pTyr followed by Western blot analysis with an antibody against EGFR. RESULTS: Both VIP receptors were present in rat conjunctiva and cultured goblet cells. VIP- and VPAC-specific agonists increased [Ca(2+)]i and secretion in a concentration-dependent manner. VIP also increased ERK1/2 activity, VIP-stimulated increase in [Ca(2+)]i. Secretion, but not ERK1/2 activity, was inhibited by the protein kinase A inhibitor, H89. VIP-stimulated secretion was inhibited by siRNA for ERK2 but not by siRNA for EGFR. VIP did not increase the phosphorylation of the EGFR. CONCLUSIONS: In conclusion, in cultured rat conjunctival goblet cells, VPAC1 and 2 receptors are functional. VIP stimulates a cAMP-dependent increase in [Ca(2+)]i and glycoconjugate secretion, but not ERK1/2 activation. VIP does not activate with EGFR.
Asunto(s)
Conjuntiva/metabolismo , Células Caliciformes/metabolismo , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Receptores de Tipo II del Péptido Intestinal Vasoactivo/metabolismo , Receptores de Tipo I del Polipéptido Intestinal Vasoactivo/metabolismo , Animales , Calcio/metabolismo , Células Cultivadas , Conjuntiva/citología , Conjuntiva/inervación , Proteínas Quinasas Dependientes de AMP Cíclico/antagonistas & inhibidores , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , ADN Complementario/genética , Glicoconjugados/metabolismo , Células Caliciformes/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/fisiología , Masculino , Mucina 5AC/metabolismo , Técnicas de Cultivo de Órganos , Sistema Nervioso Parasimpático/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de Tipo II del Péptido Intestinal Vasoactivo/agonistas , Receptores de Tipo II del Péptido Intestinal Vasoactivo/genética , Receptores de Tipo I del Polipéptido Intestinal Vasoactivo/agonistas , Receptores de Tipo I del Polipéptido Intestinal Vasoactivo/genética , Péptido Intestinal Vasoactivo/metabolismo , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
Vasoactive intestinal peptide (VIP) is a pleiotropic neuropeptide, acting as a neuromodulator and neuroprotective peptide in the CNS after injuries. We have previously described that pituitary adenylate cyclase-activating polypeptide (PACAP), another member of the same peptide family, is retinoprotective in ischemic lesions. The aim of this study was to investigate the protective potential of VIP in bilateral common carotid artery occlusion (BCCAO)-induced ischemic retinal lesion. Two-month-old rats were subjected to BCCAO and treated with intravitreal VIP injection. Their retinas were processed for histology after 2 weeks of survival. We measured the number of the cells/100 µm of the ganglion cell layer and the thickness of each layer such as the outer nuclear, outer plexiform, inner nuclear, and inner plexiform layers as well as that of the whole retina. We found that treatment with 1,000 pmol VIP, but not 100 pmol VIP, had significant protective effects in BCCAO-injured retina, as shown by the morphometric analysis. Comparing the neuroprotective effects of VIP and PACAP in BCCAO-operated retinas, PACAP was more effective, already protective at 100-pmol doses. Similar to other studies, we found that VIP must be given at least in 10 times more concentration than PACAP to achieve a similar degree of neuroprotection in the retina.
Asunto(s)
Arteria Carótida Común , Estenosis Carotídea/complicaciones , Isquemia/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Degeneración Retiniana/prevención & control , Péptido Intestinal Vasoactivo/uso terapéutico , Animales , Apoptosis/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Inyecciones Intravítreas , Isquemia/etiología , Isquemia/patología , Masculino , Modelos Neurológicos , Fármacos Neuroprotectores/farmacología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/administración & dosificación , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/uso terapéutico , Ratas , Ratas Wistar , Degeneración Retiniana/etiología , Degeneración Retiniana/patología , Neuronas Retinianas/efectos de los fármacos , Neuronas Retinianas/ultraestructura , Vasos Retinianos , Retinitis/tratamiento farmacológico , Retinitis/etiología , Retinitis/patología , Factores de Tiempo , Péptido Intestinal Vasoactivo/administración & dosificación , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
Destruction of the nigrostriatal dopaminergic pathway by the administration of 6-OHDA generates an animal model of Parkinson's disease. The main characteristic of this progressive neurological disorder is the loss of the dopaminergic neurons located in the substantia nigra pars compacta (SNc). Dopaminergic inputs from the SNc innervate the medium spiny neurons of the striatum and modulate the spontaneous activity of the primary output nuclei of the basal ganglia, globus pallidus interna, and substantia nigra pars reticulata. In our previous studies, we showed that systematically administered vasoactive intestinal peptide (VIP) is effective at reversing motor deficits, decreasing neuronal cell death, and repairing the myelin sheet in parkinsonian rats. In the current study, the effects of VIP on the dendritic morphology of the striatal neurons and the number of dopaminergic neurons in the SNc were examined in 6-OHDA-lesioned rats using Golgi-Cox staining and design-based stereological methods, respectively. Adult Sprague-Dawley rats were separated into sham-operated, bilaterally 6-OHDA lesioned and lesioned + i.p. VIP-injected (25 ng/kg) groups. VIP was first injected 1 h after the intrastriatal 6-OHDA microinjection (every 2 days for 15 days). The 6-OHDA significantly decreased the total number of dopaminergic neurons, branching, and spine density of the medium spiny neurons in the striatum. VIP significantly increased the number of neurons immunostained with tyrosine hydroxylase and the density of spines without altering the branching and the total length of dendrites. In conclusion, VIP might display synaptogenetic activity by enhancing the spine density in the striatum of the parkinsonian rats.
Asunto(s)
Antiparkinsonianos/uso terapéutico , Cuerpo Estriado/efectos de los fármacos , Neuronas Dopaminérgicas/efectos de los fármacos , Plasticidad Neuronal/efectos de los fármacos , Fármacos Neuroprotectores/uso terapéutico , Trastornos Parkinsonianos/tratamiento farmacológico , Péptido Intestinal Vasoactivo/uso terapéutico , Animales , Antiparkinsonianos/farmacología , Recuento de Células , Cuerpo Estriado/patología , Cuerpo Estriado/fisiopatología , Dendritas/efectos de los fármacos , Dendritas/ultraestructura , Neuronas Dopaminérgicas/ultraestructura , Evaluación Preclínica de Medicamentos , Fármacos Neuroprotectores/farmacología , Oxidopamina/toxicidad , Trastornos Parkinsonianos/patología , Ratas , Ratas Sprague-Dawley , Coloración y Etiquetado , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
BACKGROUND: The neurotransmitters mediating inhibitory pathways to internal anal sphincter (IAS) have not been fully characterized. Our aim was to assess the putative release of nitric oxide, purines and vasoactive intestinal peptide (VIP) from inhibitory motor neurons (MNs) and their role in the myogenic tone, resting membrane potential (RMP) of smooth muscle cells (SMC), spontaneous inhibitory junction potentials (sIJP), mechanical relaxation, and IJP induced by electrical field stimulation (EFS) or nicotine. METHODS: Rat IAS strips were studied using organ baths, microelectrodes, and immunohistochemistry. KEY RESULTS: Internal anal sphincter strips developed active myogenic tone (0.31 g), enhanced and stabilized by prostaglandin F(2α) (PGF2α). L-NNA (1 mmol L(-1)) depolarized SMC and increased tone but did not modify sIJP. In contrast, the specific P2Y(1) receptor antagonist MRS2500 (1 µmol L(-1)) did not modify the RMP or the basal tone but abolished sIJP. Electrical field stimulation and nicotine (10 µmol L(-1)) caused IAS relaxation (-45.9%VS-52.2%), partially antagonized by L-NNA (35%-45%, P ≤ 0.05) and fully abolished by MRS2500 (P ≤ 0.001). Electrical field stimulation induced a biphasic inhibitory junction potential (IJP), the initial fast component was selectively blocked by MRS2500 and the sustained slow component was blocked by L-NNA. Vasoactive intestinal peptide 6-28 (0.1 µmol L(-1)) or α-chymotrypsin (10 U mL(-1)) did not modify the RMP, sIJP, EFS-induced IJP, or relaxation. P2Y(1) receptors were immunolocalized in the circular SMC of IAS. CONCLUSIONS & INFERENCES: The effects of inhibitory MNs on rat IAS are mediated by a functional co-transmission process involving nitrergic and purinergic pathways through P2Y(1) receptors with specific and complementary roles on the control of tone, sIJP, and hyperpolarization and relaxation of IAS following stimulation of inhibitory MNs.
Asunto(s)
Adenosina Trifosfato/metabolismo , Canal Anal/inervación , Canal Anal/metabolismo , Vías Eferentes/metabolismo , Inhibición Neural/fisiología , Óxido Nítrico/metabolismo , Canal Anal/efectos de los fármacos , Animales , Vías Eferentes/efectos de los fármacos , Electrofisiología , Inhibidores Enzimáticos/metabolismo , Humanos , Masculino , Potenciales de la Membrana/efectos de los fármacos , Neuronas Motoras/efectos de los fármacos , Neuronas Motoras/metabolismo , Relajación Muscular/efectos de los fármacos , Tono Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Inhibición Neural/efectos de los fármacos , Neurotransmisores/farmacología , Nicotina/farmacología , Agonistas Nicotínicos/farmacología , Óxido Nítrico/farmacología , Purinas/farmacología , Ratas , Ratas Sprague-Dawley , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
Evidence suggests that circadian rhythms are regulated through diffusible signals generated by the suprachiasmatic nucleus (SCN). Vasoactive intestinal peptide (VIP) is located in SCN neurons positioned to receive photic input from the retinohypothalamic tract and transmit information to other SCN cells and adjacent hypothalamic areas. Studies using knockout mice indicate that VIP is essential for synchrony among SCN cells and for the expression of normal circadian rhythms. To test the hypothesis that VIP is also an SCN output signal, we recorded wheel-running activity rhythms in hamsters and continuously infused the VIP receptor agonist BAY 55-9837 in the third ventricle for 28 days. Unlike other candidate output signals, infusion of BAY 55-9837 did not affect activity levels. Instead, BAY 55-9837 lengthened the circadian period by 0.69 +/- 0.04 h (P < 0.0002 compared with controls). Period returned to baseline after infusions. We analyzed the effect of BAY 55-9837 on cultured SCN from PER2::LUC mice to determine if lengthening of the period by BAY 55-9837 is a direct effect on the SCN. Application of 10 muM BAY 55-9837 to SCN in culture lengthened the period of PER2 luciferase expression (24.73 +/- 0.24 h) compared with control SCN (23.57 +/- 0.26, P = 0.01). In addition, rhythm amplitude was significantly increased, consistent with increased synchronization of SCN neurons. The effect of BAY 55-9837 in vivo on period is similar to the effect of constant light. The present results suggest that VIP-VPAC2 signaling in the SCN may play two roles, synchronizing SCN neurons and setting the period of the SCN as a whole.
Asunto(s)
Ritmo Circadiano/fisiología , Receptores de Péptido Intestinal Vasoactivo/metabolismo , Péptido Intestinal Vasoactivo/metabolismo , Animales , Ritmo Circadiano/efectos de los fármacos , Cricetinae , Hipotálamo/metabolismo , Luz , Masculino , Mesocricetus , Ratones , Ratones Noqueados/metabolismo , Actividad Motora , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/fisiología , Fragmentos de Péptidos , Receptores de Péptido Intestinal Vasoactivo/fisiología , Transducción de Señal/fisiología , Núcleo Supraquiasmático/metabolismo , Núcleo Supraquiasmático/fisiología , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
The ventral anterior nucleus of the thalamus (VATh) gathers motor information from the internal segment of the globus pallidus (GPi) and substantia nigra pars reticulata (SNpr) of the basal ganglia and projects directly to motor areas of cortex. GPi/SNpr send their tonically active gamma-aminobutyric acid (GABA)ergic outputs to VATh. The abnormal firing patterns of GABAergic neurons in GPi/SNpr lead to motor deficits. In Parkinson's disease, the spontaneous firing pattern of GPi/SNpr neurons is abnormal due to the degeneration of the nigrostriatal dopaminergic pathway. In a previous study, we found that systemically administered vasoactive intestinal peptide (VIP) was effective at reversing the motor deficits (but not the decline in striatal dopamine levels) in a rat model of Parkinson's disease (6-hydroxydopamine (6-OHDA) exposure). In addition to the beneficial effects on the motor response, VIP could also attenuate both neuronal cell death and the characteristic loss of the myelin sheath that is associated with 6-OHDA administration into the rat striatum. VIP was thought to preserve neurons by inducing native brain mast cells to adopt a nondegranulating phenotype that had the ability to secrete numerous neuroprotective substances, such as nerve growth factor (NGF) and heparin. In the present study, the effect of systemically administered VIP (25 ng/kg i.p.) was investigated on GABA levels of the VATh, dopamine/3,4-dihydroxyphenylacetic acid (DOPAC) levels in the corpus striatum, and the NGF, rat mast cell protease II (RMCPII), serotonin, and heparin content of brain mast cells in 6-OHDA-lesioned rats. Extracellular concentrations of GABA, dopamine, and DOPAC were measured by microdialysis and high-performance liquid chromatography. NGF, RMCPII, serotonin, and heparin levels were examined by immunohistochemical staining techniques. A total of 48 young adult Sprague-Dawley rats were used in the study, and these were assigned to one of six groups. Unilateral injection of 6-OHDA, 2 microl (6 mg/microl), was made into the right corpus striatum. VIP-treated animals received 25 ng/kg VIP i.p. at 2-day intervals for a period of 15 days. The present results demonstrated that VIP significantly increased the levels of GABA in the VATh that were reduced by 6-OHDA application and increased the number of NGF-immunoreactive mast cells but did not alter dopamine metabolism. Therefore, the protective effect of VIP on motor function is possibly related to the increased levels of GABA in the VATh, and its neuroprotective actions may be mediated by the release of NGF from brain mast cells.
Asunto(s)
Mastocitos/metabolismo , Factor de Crecimiento Nervioso/metabolismo , Trastornos Parkinsonianos/tratamiento farmacológico , Trastornos Parkinsonianos/metabolismo , Tálamo , Péptido Intestinal Vasoactivo , Ácido gamma-Aminobutírico/metabolismo , Ácido 3,4-Dihidroxifenilacético/metabolismo , Animales , Femenino , Heparina/metabolismo , Masculino , Mastocitos/citología , Microdiálisis , Oxidopamina/toxicidad , Trastornos Parkinsonianos/inducido químicamente , Trastornos Parkinsonianos/fisiopatología , Ratas , Ratas Sprague-Dawley , Serotonina/metabolismo , Tálamo/citología , Tálamo/efectos de los fármacos , Tálamo/metabolismo , Péptido Intestinal Vasoactivo/farmacología , Péptido Intestinal Vasoactivo/uso terapéuticoRESUMEN
Chronic bacterial airway infections are the major cause of mortality in cystic fibrosis (CF). Normal airway defenses include reflex stimulation of submucosal gland mucus secretion by sensory neurons that release substance P (SubP). CFTR is an anion channel involved in fluid secretion and mutated in CF; the role of CFTR in secretions stimulated by SubP is unknown. We used optical methods to measure SubP-mediated secretion from human submucosal glands in lung transplant tissue. Glands from control but not CF subjects responded to mucosal chili oil. Similarly, serosal SubP stimulated secretion in more than 60% of control glands but only 4% of CF glands. Secretion triggered by SubP was synergistic with vasoactive intestinal peptide and/or forskolin but not with carbachol; synergy was absent in CF glands. Pig glands demonstrated a nearly 10-fold greater response to SubP. In 10 of 11 control glands isolated by fine dissection, SubP caused cell volume loss, lumen expansion, and mucus flow, but in 3 of 4 CF glands, it induced lumen narrowing. Thus, in CF, the reduced ability of mucosal irritants to stimulate airway gland secretion via SubP may be another factor that predisposes the airways to infections.
Asunto(s)
Regulador de Conductancia de Transmembrana de Fibrosis Quística/fisiología , Glándulas Exocrinas/metabolismo , Moco/metabolismo , Sustancia P/fisiología , Tráquea/metabolismo , Factores de Edad , Animales , Señalización del Calcio/efectos de los fármacos , Señalización del Calcio/fisiología , Capsicum/química , Carbacol/farmacología , Quelantes/farmacología , Clotrimazol/farmacología , Colforsina/farmacología , Fibrosis Quística/metabolismo , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Ácido Egtácico/análogos & derivados , Ácido Egtácico/farmacología , Glándulas Exocrinas/citología , Glándulas Exocrinas/efectos de los fármacos , Femenino , Humanos , Técnicas In Vitro , Masculino , Aceites de Plantas/farmacología , Sustancia P/farmacología , Sus scrofa , Tráquea/efectos de los fármacos , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
Pituitary adenylate cyclase-activating polypeptide (PACAP) and the proopiomelanocortin (POMC)-derived peptide, alpha-melanocyte-stimulating hormone (alpha-MSH), exert anorexigenic activities. While alpha-MSH is known to inhibit food intake and stimulate catabolism via activation of the central melanocortin-receptor MC4-R, little is known regarding the mechanism by which PACAP inhibits food consumption. We have recently found that, in the arcuate nucleus of the hypothalamus, a high proportion of POMC neurons express PACAP receptors. This observation led us to investigate whether PACAP may inhibit food intake through a POMC-dependent mechanism. In mice deprived of food for 18 h, intracerebroventricular administration of PACAP significantly reduced food intake after 30 min, and this effect was reversed by the PACAP antagonist PACAP6-38. In contrast, vasoactive intestinal polypeptide did not affect feeding behavior. Pretreatment with the MC3-R/MC4-R antagonist SHU9119 significantly reduced the effect of PACAP on food consumption. Central administration of PACAP induced c-Fos mRNA expression and increased the proportion of POMC neuron-expressing c-Fos mRNA in the arcuate nucleus. Furthermore, PACAP provoked an increase in POMC and MC4-R mRNA expression in the hypothalamus, while MC3-R mRNA level was not affected. POMC mRNA level in the arcuate nucleus of PACAP-specific receptor (PAC1-R) knock-out mice was reduced as compared with wild-type animals. Finally, i.c.v. injection of PACAP provoked a significant increase in plasma glucose level. Altogether, these results indicate that PACAP, acting through PAC1-R, may inhibit food intake via a melanocortin-dependent pathway. These data also suggest a central action of PACAP in the control of glucose metabolism.
Asunto(s)
Núcleo Arqueado del Hipotálamo/metabolismo , Ingestión de Alimentos/efectos de los fármacos , Hipotálamo/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Proopiomelanocortina/metabolismo , Animales , Núcleo Arqueado del Hipotálamo/efectos de los fármacos , Glucemia/análisis , Corticosterona/sangre , Relación Dosis-Respuesta a Droga , Ingestión de Alimentos/fisiología , Hipotálamo/efectos de los fármacos , Masculino , Hormonas Estimuladoras de los Melanocitos/farmacología , Ratones , Ratones Noqueados , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuropéptido Y/metabolismo , Fragmentos de Péptidos/farmacología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/antagonistas & inhibidores , Proopiomelanocortina/genética , ARN Mensajero/metabolismo , Receptor de Melanocortina Tipo 3/antagonistas & inhibidores , Receptor de Melanocortina Tipo 3/metabolismo , Receptor de Melanocortina Tipo 4/antagonistas & inhibidores , Receptor de Melanocortina Tipo 4/metabolismo , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/genética , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
Neuroblastoma is a pediatric tumor which can spontaneously regress or differentiate into a benign tumor. MYCN oncogene amplification occurs in 22% of neuroblastomas and is associated with poor prognosis. Retinoic acid (RA), a molecule able to induce differentiation and to decrease MYCN expression, is used in the therapy of neuroblastomas. The neuropeptide vasoactive intestinal peptide (VIP) is known to control proliferation or differentiation of numerous cancer cells. In vitro, VIP induces differentiation of neuroblastoma cells. To determine whether VIP could modulate MYCN expression, we carried out real-time quantitative RT-PCR and Western immunoblot analyses in human neuroblastoma SH-SY5Y and IMR-32 cells. The results indicated that VIP reduced MYCN mRNA and protein expression, especially in the MYCN-amplified IMR-32 cells, with a maximal and transient decrease by approximately 50% after few hours of treatment with VIP at 10(-6) M. This effect was compared to that of RA at 10(-5) M, which induced a diminution of MYCN mRNA expression by approximately 25% after few days of treatment. This indicated that VIP and RA display complementary kinetics. Cotreatments showed that VIP and RA had synergistic effects on regulation of expression of MYCN proteins. VIP and RA cotreatments regulated also expression of two MYCN target genes, SKP2 and TP53INP1. These results suggest that VIP, in combination with RA may have a potential therapeutic benefit in neuroblastomas with MYCN amplification, a genetic abnormality associated with poor prognosis.
Asunto(s)
Antineoplásicos/farmacología , Neuroblastoma/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Oncogénicas/metabolismo , Tretinoina/farmacología , Péptido Intestinal Vasoactivo/farmacología , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Forma de la Célula/efectos de los fármacos , Regulación hacia Abajo , Sinergismo Farmacológico , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Proteínas de Choque Térmico/metabolismo , Humanos , Cinética , Proteína Proto-Oncogénica N-Myc , Neuroblastoma/genética , Neuroblastoma/patología , Proteínas Nucleares/genética , Proteínas Oncogénicas/genética , ARN Mensajero/metabolismo , Proteínas Quinasas Asociadas a Fase-S/metabolismoRESUMEN
Peptide histidine isoleucine (PHI) and vasoactive intestinal peptide (VIP) are neuropeptides synthesized from a common precursor, prepro-VIP, and share structural similarity and biological functions in many systems. Within the central nervous system and peripheral tissues, PHI and VIP have overlapping distribution. PHI-mediated functions are generally via activation of VIP receptors; however, the potency and affinity of PHI for VIP receptors are significantly lower than VIP. In addition, several studies suggest distinct PHI receptors that are independent of VIP receptors. PHI receptors have been cloned and characterized in fish, but their existence in mammals is still unknown. This study focuses on the functional role of PHI in the thalamus because of the localization of both PHI and VIP receptors in this brain region. Using extracellular multiple-unit recording techniques, we found that PHI strongly attenuated the slow intrathalamic rhythmic activity. Using intracellular recording techniques, we found that PHI selectively depolarized thalamic relay neurons via an enhancement of the hyperpolarization-activated mixed cation current, Ih. Further, the actions of PHI were occluded by VIP and dopamine, indicating these modulators converge onto a common mechanism. In contrast to previous work, we found that PHI was more potent than VIP in producing excitatory actions on thalamic neurons. We next used the transgenic mice lacking a specific VIP receptor, VPAC2, to identify its possible role in PHI-mediated actions in the thalamus. PHI depolarized all relay neurons tested from wild-type mice (VPAC2(+/+)); however, in knockout mice (VPAC2(-/-)), PHI produced no change in membrane potential in all neurons tested. Our findings indicate that excitatory actions of PHI are mediated by VPAC2 receptors, not by its own PHI receptors and the excitatory actions of PHI clearly attenuate intrathalamic rhythmic activities, and likely influence information transfer through thalamocortical circuits.