Eficácia e segurança de Riociguate comparado ao placebo e a medicamentos disponíveis no sus para tratamento de hipertensão pulmonar tromboembólica crônica: revisão rápida de evidências / Effectiveness and safety of Riociguate compared to placebo and drugs available in brazilian public health for treatment of chronic thromboembolic pulmonary hypertension: rapid response review of evidence

Tecnologia: Riociguate e outros medicamentos de controle da hipertensão pulmonar. Indicação: Tratamento de Hipertensão Pulmonar Tomboembólica Crônica (HPTEC). Pergunta: Há superioridade em eficácia e segurança do riociguate, comparado a medicamentos disponíveis no SUS, no tratamento de HPTEC inoperável ou operada com hipertensão pulmonar residual? Métodos: Revisão rápida de evidências (overview) de revisões sistemáticas, com levantamento bibliográfico realizado na base de dados PUBMED, utilizando estratégia estruturada de busca. A qualidade metodológica das revisões sistemáticas foi avaliada com AMSTAR-2 (Assessing the Methodological Quality of Systematic Reviews). Resultados: Foram selecionadas 4 e incluídas 2 revisões sistemáticas. Conclusão: Comparado ao placebo, em tratamento de curto prazo de HPTEC, riociguate melhora a tolerância ao exercício, aumenta a chance de melhora da classificação funcional e tem similar risco de eventos adversos sérios, porém não reduz a mortalidade. Treprostinil tem efeitos similares a riociguate. Entretanto, ambrisentana, bosentana, macitentana ou sildenafila não diferem do placebo no tratamento de HPTEC

Technology: Riociguat and other drugs to control pulmonary hypertension. Indication: Treatment of chronic thromboembolic pulmonary hypertension (CTEPH). Question: Is riociguat more effective and safe than other drugs available in the Brazilian Public Health System for the treatment of inoperable or recurrent CTEPH? Methods: Rapid review of evidence (overview) from systematic reviews, with a bibliographic search in the PUBMED database, using a structured strategy. The methodological quality of systematic reviews was assessed with AMSTAR-2 (Methodological Quality Assessment of Systematic Reviews). Results: Four systematic reviews were selected and two included in this study. Conclusion: Compared to placebo, in the short-term treatment of CTEPH, riociguat improves exercise tolerance, increases the chance of improving functional classification, and has a similar risk of serious adverse events, but does not reduce mortality. Treprostinil has similar effects to riociguat. However, ambrisentan, bosentan, macitentan or sildenafil do not differ from placebo in the treatment of CTEPH

Vascular interactions of Croton schiedeanus major flavonoids in isolated aortic rings from Wistar rats / Interacciones vasculares de los principales flavonoides de Croton schiedeanus en anillos aislados de aorta de ratas Wistar

Background: Ayanin (3,7,4'-Tri-O-methylquercetin) and 3,7-Di-O-methylquercetin (DMQ) are the main active metabolites isolated by bioguided fractionation from Croton schiedeanus, species known popularly in Colombia as "almizclillo", which has been studied in experimental models in rats, exerting vasodilator and antihypertensive effects. Also, when the effect of these flavonoids was studied separately, important vasodilation was observed. Objective:To evaluate whether flavonoids from Croton schiedeanus have synergistic vasodilator properties when different combinations are used in isolated aorta rings. Methods: Cumulative concentrations of ayanin (10-8 M - 6x10-5 M or 0.01 µM - 60 µM) were assayed in the absence and presence of an increasing concentration of 3,7-Di-O-methylquercetin (DMQ) (10-8 ­ 3x10-5M or 0.01­30 µM) in isolated rings from Wistar rats, pre-contracted with phenylephrine. The concentration-response curve with the maximal effect was compared with that obtained by Croton schiedeanus whole ethanolic extract (10-6 ­ 3x10-4 g/mL). Also, this combination was assayed in the presence of the nitric oxide synthetase inhibitor L-NAME (10-4 M) and the guanylate cyclase inhibitor methylene blue (10-4 M) to assess the role of the NO/cGMP pathway in this interaction. Results: Ayanin and DMQ display a dual interaction in vascular relaxant response: agonism at higher concentration ranges (10-6 ­ 3x10-5 M or 1­30 µM) and antagonism at lower concentration ranges (10-8 ­ 3x10-7 M or 0.01­0.3 µM). The efficacy at the highest concentration was greater than that obtained by the whole extract (Emax: 98.4% vs. 33.9%). This response was decreased but not reverted in the presence of L-NAME and methylene blue. Thus, the vasodilator effect of this combination does not depend entirely on the NO/cGMP cyclic pathway. Conclusion: The combined use of appropriate concentrations of these flavonoids could represent an advantage over Croton schiedeanus whole extract for vasodilator purposes

Antecedentes: Ayanina (3,7,4'-Tri-O-metilquercetina) y 3,7-Di-O-metilquercetina (DMQ) son los principales metabolitos activos aislados mediante fraccionamiento bioguiado, a partir de Croton schiedeanus, especie conocida popularmente en Colombia como "almizclillo", la cual ha sido estudiada en modelos experimentales en ratas, ejerciendo efectos antihipertensivos y vasodilatadores. Además, al estudiar por separado el efecto de los flavonoides, se observó importante vasodilatación. Objetivo:Evaluar si los principales flavonoides de Croton schiedeanus tienen propiedades vasodilatadoras sinérgicas al utilizar diferentes combinaciones de ellos en anillos de aorta aislados. Metodología: Se analizaron concentraciones acumulativas de ayanina (10-8 M - 6x10-5 M o 0,01 µM - 60 µM) en ausencia y en presencia de concentraciones crecientes de DMQ (10-8 M - 3x10-5 M o 0,01 µM ­ 30 µM) en anillos aislados de ratas Wistar, pre-contraídos con fenilefrina. La curva concentración respuesta obtenida con el efecto máximo, fue comparada con la obtenida con el extracto etanólico de Croton schiedeanus (10-6 - 3x10-4 g/mL). Adicionalmente, esta combinación fue ensayada en presencia del inhibidor de óxido nítrico sintetasa L-NAME (10-4 M) y el inhibidor de guanilato ciclasa, azul de metileno (10-4 M) para evaluar el papel de la vía NO/GMPc en esta interacción. Resultados: Ayanina y DMQ muestran una interacción dual en la respuesta vascular relajante: agonismo en el rango más alto (10-6 M ­ 3x10-5 M o 1 µM ­ 30 µM), y antagonismo en el rango más bajo (10-8 M ­ 3x10-7 M o 0.01 µM ­ 0,3 µM). A altas concentraciones, la eficacia de los flavonoides fue mayor que las obtenidas por el extracto completo (Emáx: 98,4% vs 33,9%). Esta respuesta disminuyó, pero no se revirtió en presencia de L-NAME y azul de metileno. Por lo tanto, el efecto vasodilatador de esta combinación no depende enteramente de la vía NO/GMPc. Conclusión: El uso combinado de las concentraciones apropiadas de estos flavonoides podría representar una ventaja sobre el extracto de Croton schiedeanus, con propósitos vasodilatadores

Highly Expression and Purification of an Antigenic Region (D259-R462) of Adenylate Guanylate Cyclase Protein, Applicable for ELISA Test

Abstract Leptospirosis is a wide spread bacterial zoonosis that is common worldwide. The disease symptoms are mild or acute. Leptospira has pathogenic and non-pathogenic species; it has a lot of surface antigens. Adenylate Guanylate Cyclase (AGC) is a membrane protein that is found only in pathogenic species. In this study, the complete coding sequences of AGC protein of 242 pathogen serovars were investigated by bioinformatics tools. A Pattern was selected as a target sequence based on high prevalence pathogenic serovars in Iran Antigen sites; moreover, B-cell and T-cell epitopes were predicted by IEDB web server. An antigen site amino acid (D259-R462) in complete coding sequence of AGC protein was selected. This nucleotide related sequence was cloned into the pET32a+ expression vector. Expression of recombinant protein was optimized in E. coli strain Bl21-DE3 by 0.2mM IPTG after 16-hour incubation at 37 ͦ C and confirmed by 10% SDS-PAGE and western blotting. Antigenic peptide D259-R462 was highly expressed as Trx tag fusion protein. Recombinant peptide (rAcB) was purified by 6M urea from inclusion body with high extent yield 514.2 mg per 1000ml culture of E. coli. 20µg rAcB protein with montanide adjuvant was injected subcutaneously in BALB/c mice. Results showed that the recombinant peptide D259-R462 was produced significant antibody compared to adjuvant and PBS groups. The induced antibody in sera of immunized animal with Leptospira vaccine was detected by 250 ng of rAcB coated in ELISA microplate. This study demonstrated that antigenic region (D259-R462) of AGC protein might be useful for evaluation of antibody level in vaccinated animal.

Variants of CARD14 gene and psoriasis vulgaris in southern Chinese cohort

Abstract BACKGROUND: Recent mutation analysis identified several missense mutations in CARD14 in psoriasis. OBJECTIVES: We performed the genomic sequence analysis on CARD14 in southern Chinese Han Cantonese with Psoriasis Vulgaris (PsV) to reveal more causative missense mutations. METHODS: A total of 131 patients with PsV and 207 matched controls were included. We conducted sequence analysis of all the exon and exon-intron boundaries of CARD14 in the group of PsV patients and subsequent case control analysis of potential sequence variants of significance. RESULTS: We found five rare mutations and four of them are annotated or reported. Only the variant (c.1291C>G) has not been reported and annotated, but the variant was also found in controls. No significant difference was detected among all rare variant allele frequencies of patients and controls. CONCLUSION: None of the new definite variants were pathogenic. The other pathogenic mutations for PsV are still elusive in our cohort.

Efeito protetor do complexo de rutênio (II) (cis-[RuCl(qui)(bpy)2]PF6) contra a lesãogástrica induzida por naproxeno: possível papel regulador da enzima guanilato ciclase solúvel

Os AINEs são um dos principais agentes que contribuem para a patogênese da úlcera gastrintestinal e representam um importante fator etiológico por serem comum enteutilizados na prática clínica. Objetivo: Avaliar o efeito protetor do complexo de rutênio (II)(cis-[RuCl(qui)(bpy)2]PF6), contra a lesão gástrica induzida por na proxeno (NPX) em camundongos. Métodos: Foram utilizados camundongos Swiss (18-22g). Mensuramos os níveis de GMPc incubando amostras de tecidos gástricos com DMSO, com o complexo de Ru (II) e com ODQ, 30 μm de cada composto, por 5 minutos. Os grupos avaliados foram: grupo controle que recebeu CMC, grupo veículo, em que foi administrado NPX (300 mg/kg)e o que recebeu complexo de Ru (II), todos por gavagem. Os animais foram tratados com o complexo de Ru (II), nas doses de 0,3, 3 e 30 mg/kg. Após 30 minutos, seguiu-se com a indução da lesão com NPX. Seguindo o mesmo protocolo,avaliou-se o efeito do composto em estudo e de seus precursores, na dose de 3mg/kg, por gavagem.Verificou-se o efeito do composto na adesão e rolamento leucocitários; seguindo os protocolos descritos, tanto o rolamento quanto a adesão foram avaliados 3h após a indução de gastropatia e de modulação com ODQ (10 mg/kg) por gavagem. Analisou-se o efeito do complexo de Ru (II)em artérias mesentéricas de ratos wistar(200-250g) pré-contraídas com fenilefrina(PHE)(0,3 μM). Simulou-sea ligação entre o composto e a enzima GCs a partir de recursos disponíveis em site que contém banco de dados de proteínas...

NSAIDs contribute to the pathogenesis of gastrointestinal ulcers and represent an important etiologic factor because iscommonly used in clinical practice. Aim:To evaluate the protective effect of the ruthenium complex (II) (cis-[RuCl(qui)(bpy)2]PF6), against the gastric damageinduced by naproxen(NPX)in mice. Methods: Swiss mice were used (18-22g). Measure the GMPc levels incubating samples of gastric tissues with DMSO, with the complex of RU (II) and with ODQ, 30 μm of each compound, for 5 minutes. The groups evaluated were: control group that received CMC, group vehicle, in which was administered NPX (300 mg/kg) and who received complex of RU (II), all by gavage. The animals were treated with the complex of RU (II), in the doses of 0.3, 3 and 30 mg/kg. After 30 minutes, was followed with the induction of the lesion with NPX. Following the same protocol, it was evaluated the effect of the compound and its precursors, in dose of 3mg/kg, by gavage. It was verified theeffect of compound in accession and leukocyte bearing; following the protocols described, both the bearing for accession were evaluated 3h after the induction of gastropathy and modulation with ODQ (10 mg/kg) by gavage. It examined the effect of the complex of RU (II) in mesenteric arteries of Wistar rats (200-250 g) pre-contracted with phenylephrine (PHE) (0.3 μM). Simulated-If the connection between the compound and the enzyme GCs from resources available in the site that contains the database of proteins...

Activation of locus coeruleus heme oxygenase-carbon monoxide pathway promoted an anxiolytic-like effect in rats

The heme oxygenase-carbon monoxide pathway has been shown to play an important role in many physiological processes and is capable of altering nociception modulation in the nervous system by stimulating soluble guanylate cyclase (sGC). In the central nervous system, the locus coeruleus (LC) is known to be a region that expresses the heme oxygenase enzyme (HO), which catalyzes the metabolism of heme to carbon monoxide (CO). Additionally, several lines of evidence have suggested that the LC can be involved in the modulation of emotional states such as fear and anxiety. The purpose of this investigation was to evaluate the activation of the heme oxygenase-carbon monoxide pathway in the LC in the modulation of anxiety by using the elevated plus maze test (EPM) and light-dark box test (LDB) in rats. Experiments were performed on adult male Wistar rats weighing 250-300 g (n=182). The results showed that the intra-LC microinjection of heme-lysinate (600 nmol), a substrate for the enzyme HO, increased the number of entries into the open arms and the percentage of time spent in open arms in the elevated plus maze test, indicating a decrease in anxiety. Additionally, in the LDB test, intra-LC administration of heme-lysinate promoted an increase on time spent in the light compartment of the box. The intracerebroventricular microinjection of guanylate cyclase, an sGC inhibitor followed by the intra-LC microinjection of the heme-lysinate blocked the anxiolytic-like reaction on the EPM test and LDB test. It can therefore be concluded that CO in the LC produced by the HO pathway and acting via cGMP plays an anxiolytic-like role in the LC of rats.

From Escherichia coli heat-stable enterotoxin to mammalian endogenous guanylin hormones

The isolation of heat-stable enterotoxin (STa) from Escherichia coli and cholera toxin from Vibrio cholerae has increased our knowledge of specific mechanisms of action that could be used as pharmacological tools to understand the guanylyl cyclase-C and the adenylyl cyclase enzymatic systems. These discoveries have also been instrumental in increasing our understanding of the basic mechanisms that control the electrolyte and water balance in the gut, kidney, and urinary tracts under normal conditions and in disease. Herein, we review the evolution of genes of the guanylin family and STa genes from bacteria to fish and mammals. We also describe new developments and perspectives regarding these novel bacterial compounds and peptide hormones that act in electrolyte and water balance. The available data point toward new therapeutic perspectives for pathological features such as functional gastrointestinal disorders associated with constipation, colorectal cancer, cystic fibrosis, asthma, hypertension, gastrointestinal barrier function damage associated with enteropathy, enteric infection, malnutrition, satiety, food preferences, obesity, metabolic syndrome, and effects on behavior and brain disorders such as attention deficit, hyperactivity disorder, and schizophrenia.

Effects of nitric oxide on magnocellular neurons of the supraoptic nucleus involve multiple mechanisms

Physiological evidence indicates that the supraoptic nucleus (SON) is an important region for integrating information related to homeostasis of body fluids. Located bilaterally to the optic chiasm, this nucleus is composed of magnocellular neurosecretory cells (MNCs) responsible for the synthesis and release of vasopressin and oxytocin to the neurohypophysis. At the cellular level, the control of vasopressin and oxytocin release is directly linked to the firing frequency of MNCs. In general, we can say that the excitability of these cells can be controlled via two distinct mechanisms: 1) the intrinsic membrane properties of the MNCs themselves and 2) synaptic input from circumventricular organs that contain osmosensitive neurons. It has also been demonstrated that MNCs are sensitive to osmotic stimuli in the physiological range. Therefore, the study of their intrinsic membrane properties became imperative to explain the osmosensitivity of MNCs. In addition to this, the discovery that several neurotransmitters and neuropeptides can modulate their electrical activity greatly increased our knowledge about the role played by the MNCs in fluid homeostasis. In particular, nitric oxide (NO) may be an important player in fluid balance homeostasis, because it has been demonstrated that the enzyme responsible for its production has an increased activity following a hypertonic stimulation of the system. At the cellular level, NO has been shown to change the electrical excitability of MNCs. Therefore, in this review, we focus on some important points concerning nitrergic modulation of the neuroendocrine system, particularly the effects of NO on the SON.

Inibição da guanilato ciclase pelo azul de metileno no choque circulatório causado por pancreatite aguda necrosante: uma palavra de cuidado embasada em modelo suíno / Guanylate cyclase inhibition by methylene blue in circulatory shock caused by acute necrotizing pancreatitis: a word of caution based on a porcine model

OBJETIVO: estudar o uso terapêutico do bloqueio da guanilato ciclase pelo azul de metileno em um modelo experimental de pancreatite aguda grave em suínos. MÉTODOS: a pancreatite aguda necrotizante foi induzida em porcos anestesiados por infusão ductal pancreática retrógrada de 1ml/kg de taurocolato de sódio a 5% e 8U/kg de enteroquinase. Três grupos foram estudados (n=5): controle (C), pancreatite (PA), "bolus" de azul seguido por pancreatite (AM+PA). Os dados incluíram enzimas séricas e do líquido abdominal, variáveis hemodinâmicas, hemogasometria arterial, volume de líquido abdominal, marcadores inflamatórios plasmáticos, nitrito/nitrato e mieloperoxidase e malondialdeído plasmático. Aplicou-se a análise de variância seguida do pós-teste de Bonferroni (p<0,05). RESULTADOS: os valores de amilase e lipase foram três e dez vezes mais elevados no grupo PA. A atividade da mieloperoxidase foi 50% superior no grupo PA. Os dados hemodinâmicos indicaram choque hipovolêmico precoce seguido de choque cardiogênico. Observou-se grave translocação de líquidos para a cavidade peritoneal. A nitrito/nitrato plasmática permaneceu inalterada. O grupo AM+PA teve aumento de cinco vezes do mieloperoxidase em comparação com o grupo C. CONCLUSÕES: a utilização de azul de metileno em suínos com pancreatite não demonstrou efeitos significativos sobre variáveis hemodinâmicas e inflamatórias. Seu uso terapêutico na pancreatite necro-hemorrágica pode ser inadequado e extremo cuidado deve ser tomado dado o aumento da peroxidação lipídica evidenciado pelo aumento dos valores do malondialdeído.

OBJECTIVE: To study the therapeutic application of guanylate cyclase inhibition by methylene blue in an experimental model of acute pancreatitis in pigs. METHODS: acute necrotizing pancreatitis was induced in anesthetized pigs by the retrograde infusion of 1 ml/kg of 5% sodium taurocholate and 8 U/kg enterokinase in the pancreatic duct. Three groups were studied (n = 5): control (C), pancreatitis (AP), and MB bolus followed by pancreatitis (MB+P). The data included serum and abdominal fluid enzymes, hemodynamic variables, arterial hemogasometry, abdominal fluid volume, inflammatory markers, plasma nitrite/nitrate (NOx), plasma myeloperoxidase (MPO) and plasma malondialdehyde (MDA). One- and two-way analysis of variance (ANOVA) was performed, followed by the Bonferroni test (p < 0.05). RESULTS: amylase and lipase were three and 10-fold higher in the AP group. Myeloperoxidase activity was 50% higher in the AP group. The hemodynamic data indicated early hypovolemic shock followed by cardiogenic shock. Severe fluid translocation to the peritoneal cavity was observed. Plasma NOx remained unchanged. The MB+P group had a five-fold increase in MDA compared with the C group. CONCLUSION: preemptive application of MB in pigs with AP demonstrated no significant effects on hemodynamic and inflammatory variables. The use of MB is inadequate in cases of exponential NO release, and extreme caution must be exercised, given the increase in lipid peroxidation based on the malondialdehyde dosage.

Ionic imbalance and lack of effect of adjuvant treatment with methylene blue in the hamster model of leptospirosis

Leptospirosis in humans usually involves hypokalaemia and hypomagnesaemia and the putative mechanism underlying such ionic imbalances may be related to nitric oxide (NO) production. We previously demonstrated the correlation between serum levels of NO and the severity of renal disease in patients with severe leptospirosis. Methylene blue inhibits soluble guanylyl cyclase (downstream of the action of any NO synthase isoforms) and was recently reported to have beneficial effects on clinical and experimental sepsis. We investigated the occurrence of serum ionic changes in experimental leptospirosis at various time points (4, 8, 16 and 28 days) in a hamster model. We also determined the effect of methylene blue treatment when administered as an adjuvant therapy, combined with late initiation of standard antibiotic (ampicillin) treatment. Hypokalaemia was not reproduced in this model: all of the groups developed increased levels of serum potassium (K). Furthermore, hypermagnesaemia, rather than magnesium (Mg) depletion, was observed in this hamster model of acute infection. These findings may be associated with an accelerated progression to acute renal failure. Adjuvant treatment with methylene blue had no effect on survival or serum Mg and K levels during acute-phase leptospirosis in hamsters. .

Selective mastoporan inhibition of muscarinic activation of bovine tracheal smooth muscle

Muscarinic activation of bovine tracheal smooth muscle (BTSM) leading to smooth muscle contraction involves the generation of two cGMP signals (20 and 60 s), being 20s peak associated with soluble (sGC) and the second (60s) to membrane-bound Natriuretic Peptide- receptor-Guanylylcy clases (NPR-GC). In this study, we showed that pre-incubation of isolated BTSM strips with mastoparan and superactive mastoparan (mastoparan 7) decreased significantly the muscarinic dependent contractile smooth muscle responses in dose-dependent and non-competitive manner. Moreover, mastoparan (50 nM) inhibited completely the BTSM-muscarinic contractile responses and affected dramatically the carbachol-dependent cGMP signals being the first cGMP signal inhibited in a 63 ± 5%, whereas the second signal disappeared. Mastoparan inhibition of muscarinic activation is specific since other spasmogens as serotonin and histamine fully contracted these BTSM strips under mastoparan treatment. Cyclic GMP levels were evaluated by exposing BTSM strips to activators of NO-sensitive sGC as Sodium Nitroprussiate (SNP) and Natriuretic Peptides as CNP-53 for membrane-bound NPR-GC. Thus, SNP and CNP increased in a binary way, in more than 20 fold cGMP levels at 30-40 s being both increments inhibited by mastoparan. Furthermore, the Gi/o-protein involvement on mastoparan inhibition of cGMP elevations induced by CNP and SNP is suggested by Pertussis toxin pre-treatment, which reversed mastoparan effects. These results indicate that muscarinic signal transduction cascades leading to airway smooth muscle contractions involved two different guanylyl cyclases being both regulated by mastoparan-sensitive G-proteins. ANP, Natriuretic Peptide type A; ASM, Airway Smooth Muscle; BTSM, Bovine Tracheal Smooth Muscle; CNP-53, Natriuretic Peptide type C-53; GPCR, G-Protein Coupled Receptor; Gq16, Heterotrimeric G protein subtype 16; Gi/o, Heterotrimeric G protein subtype...

La activación muscarínica del músculo liso de las vías aéreasrelacionada a la contracción de dicho músculo liso esta asociada a la generación de dos señales de GMPc (20 y 60 s), siendo la señal de los 20s relacionado a la activación de la guanililciclasa soluble mientras que el pico de los 60s a la guanililciclasa unida membranas y sensible a péptidos natriuréticos (NPR-GC). En este trabajo, nosotros mostramos que la pre-incubación de fragmentos del músculo liso traqueal de bovino (BTSM) con mastoparan y su análogo superactivo (mastoparan 7), en una forma dosis dependiente, son capaces de disminuir de manera significativa la actividad contráctil dependiente de agentes muscarinicos. Adicionalmente, mastoparan (50 nM) inhibió completamente la respuesta contráctil muscarinica del BTSM y afectó dramáticamente los picos de GMPc asociados a la activación muscarinica siendola primera señal inhibida en un 63 ± 5%, mientras que la segunda señal desapareció completamente. Esta inhibición del mastoparan de la activación muscarínica es especifica ya que otros espamogenos como la serotonina y la histamina fueron capaces de inducir respuestas máximas en presencia del mastoparan y su análogos. Este efecto del mastoparan sobre los niveles del GMPc fue evaluado en presencia de otros agentes generadores de este segundo mensajero como son el nitroprusiato de sodio (SNP) que activa la guanililciclasa soluble sensible a NO y los péptidos natriureticos como el CNP-53 (CNP) activador de la NPR-GC asociada a membranas plasmáticas. Tanto, el SNP como el CNP aumentaronen mas de 50 veces los niveles de GMPc a los 30-40 s en forma bifasica, siendo estos incrementos inhibidos de manera significativa por el mastoparan. Ademas, se sugiere la participación de proteínas Gi/o en los efectos inhibitoriosdel mastoparan, porque la Toxina pertussis revertió los efectos inhibitorios. Estos resultados indican que la cascada de activación muscarinica que conduce...

Methylene blue for vasoplegic syndrome treatment in heart surgery: fifteen years of questions, answers, doubts and certainties / Azul de metileno no tratamento da síndrome vasoplégica em cirurgia cardíaca: quinze anos de perguntas, respostas, dúvidas e certezas

OBJECTIVE: There is strong evidence that methylene blue (MB), an inhibitor of guanylate cyclase, is an excellent therapeutic option for vasoplegic syndrome (VS) treatment in heart surgery. The aim of this article is to review the MB's therapeutic function in the vasoplegic syndrome treatment. METHODS: Fifteen years of literature review. RESULTS: 1) Heparin and ACE inhibitors are risk factors; 2) In the recommended doses it is safe (the lethal dose is 40 mg/kg); 3) The use of MB does not cause endothelial dysfunction; 4) The MB effect appears in cases of nitric oxide (NO) up-regulation; 5) MB is not a vasoconstrictor, by blocking of the GMPc system it releases the AMPc system, facilitating the norepinephrine vasoconstrictor effect; 6) The most used dosage is 2 mg/kg as IV bolus followed by the same continuous infusion because plasmatic concentrations strongly decays in the first 40 minutes; 7) There is a possible "window of opportunity" for the MB's effectiveness. CONCLUSIONS: Although there are no definitive multicentric studies, the MB used to treat heart surgery VS, at the present time, is the best, safest and cheapest option, being a Brazilian contribution for the heart surgery

OBJETIVO: Existem fortes evidências de que o azul de metileno (AM), um inibidor da guanilato ciclase, é uma excelente opção terapêutica para o tratamento da síndrome vasoplégica (SV) em cirurgia cardíaca. O objetivo deste artigo é rever o papel terapêutico do AM no tratamento da SV. MÉTODOS: Revisão da literatura em período de 15 anos. RESULTADOS: 1) A heparina e inibidores da ECA são fatores de risco; 2) Nas doses preconizadas é droga segura (a dose letal é de 40 mg/kg); 3) O AM não causa disfunção endotelial; 4) O efeito do AM só aparece em caso de supra-regulação de óxido nítrico (NO); 5) O AM não é um vasoconstritor, pelo bloqueio do sistema GMPc ele "libera" o sistema AMPc, facilitando o efeito vasoconstritor da noradrenalina; 6) A dosagem mais utilizada é 2 mg/kg em bolus endovenosa, seguida de infusão contínua, pois a concentração plasmática decai acentuadamente nos primeiros 40 minutos; 7) Existe possível "janela de oportunidade" para efetividade do AM. CONCLUSÃO: Embora não existam estudos multicêntricos definitivos, a utilização do AM no tratamento da SV em cirurgia cardíaca é, na atualidade, a melhor, mais segura e barata opção, sendo contribuição brasileira

Antinociception synergy between the peripheral and spinal sites of the heme oxygenase-carbon monoxide pathway

We have shown that the peripheral and spinal cord heme oxygenase (HO)-carbon monoxide (CO)-soluble guanylate cyclase-cGMP pathways play an important role in antinociception in the rat experimental formalin model. Our objective was to determine if there is synergism between peripheral (paw) and spinal HO-CO pathways in nociception. Rats were handled and adapted to the experimental environment for a few days before the formalin test, in which 50 µL of a 1 percent formalin was injected subcutaneously into the dorsal surface of the right hind paw. The animals were then observed for 1 h and the frequency of flinching behavior was taken to represent the nociceptive response. Thirty minutes before the test, rats were pretreated with intrathecal injections of the HO inhibitor, zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG) or heme-lysinate, which is a substrate of the HO pathway. The paw treatments took place 20 min before the test. Low doses of ZnDPBG did not increase nociception, while a low heme-lysinate dose did not change flinching behavior after paw or spinal injections. Combined subactive spinal (50 nmol) and peripheral (40 nmol) low doses of ZnDPBG induced hypernociception (increase of 80 percent in the first and 25 percent in the second phase flinching), whereas combined spinal-peripheral heme-lysinate (50 and 30 nmol) led to second phase antinociception (40 percent reduction in flinching). These findings suggest a synergy between the peripheral and spinal HO-CO pathways. Local activation of the HO system probably regulates the nociception initiation in peripheral tissue and participates in buffering the emerging nociceptive signals at the peripheral and spinal sites of action. In short, an antinociceptive synergy exists between peripheral and spinal HO pathways, which may reduce the doses required and side effects.

Efeito protetor da via hemeoxigenase 1/Biliverdina/CO em modelos de lesões gástricas em camundongos [manuscrito]: papel da guanilato ciclase solúvel (GCS) e da sintase (NOS) / Protective effect track hemeoxigenase 1 / biliverdin / CO in models of gastric lesions in mice [manuscript]: role of soluble guanylate cyclase (GCS) and synthase (NOS)

Avaliar o efeito protetor da via hemeoxigenase 1 (HO-1)/ biliverdina/ CO em modelos de gastropatia em camundongos e o papel da guanilato ciclase solúvel (GCs) e da NOS constitutiva neste evento. Métodos: Protocolo 1: Camundongos foram pré-tratados hemina (indutor da HO-1; 1,3 ou 10mg/kg, i.p.), biliverdina (produto da HO-1; 1,3 ou 1mmg/kg, i.p.), DMDC (doador de CO; 2,5, 7,5, 12,5 ou 25 μmol;kg, i.p.) ou ZnPP I (inibidor da HO-1; 0,3, 1,0 ou 3,0 mg/kg, i.p.) uma hora antes da administração por gavagem de etanol 50% (hemina, biliverdina, DMDC) ou 25% (ZnPP IX). Em outro grupo, os animais foram pré-tratados com ODQ (12,5 mg/kg, v.o.) ou L-NAME (3 mg/kg, v.o.), trinta minutos antes dos tratamentos citados anteriormente. Depois de 1h, os camundongos foram sacrificados e os estômagos removidos para avaliação das lesões gástricas (Image J). Protocolo 2: Camundongos foram pré-tratados hemina (3,0 mg/kg), biliverdina (3,0 mg/kg), DMDC (12,5 μmol/kg) ou ZnPP IX (3,0 mg/kg) uma hora antes da administração de INDO 30 mg/kg (hemina, biliverdina, DMDC) ou 10 mg/kg (ZnPP IX). Em outro grupo os animais foram pré-tratados com ODQ (12,5 mg/kg, v.o.) ou L-NAME (3 mg/kg, v.o.), trinta minutos antes dos tratamentos citados anteriormente. Três horas depois, os camundongos foram sacrificados e os estômagos removidos para avaliação das lesões gástricas, utilizando um paquímetro digital...

Um estudo renal das interações entre uroguanilina, urodilatina e bradicinina na presença dos bloqueadores da guanilato ciclase isatin e ODQ / A kidney study of interactions between uroguanylin, urodilatin and bradykinin in the presence of blockers guanylate cyclase isatin and ODQ

Guanilinas, peptídeos natriuréticos (ANP e urodilatina) e bradicinina estão implicados na fisiopatologia, com potencial terapêutico, do metabolismo do sal e da hipertensão. Objetivo: Estudar o mecanismo de ação e possíveis interações destes peptídeos, pelo emprego de inibidores de guanilato ciclase isatina e ODQ. Método: Foram realizadas experiências no rim isolado e perfundido de rato com ferramentas farmacológicas, isatina (IS; 0,3 ou 10μM) ou com ODQ (37μM), nos estudos com uroguanilina (UGN; 0,3 ou 0,6 μM), bradicinina (BK; 0,3 ou 0,9 ou 1,8nM) ou urodilatina (UD; 0,03nM). Investigaram-se ainda possíveis interações entre os referidos peptídeos. Resultados: Isoladamente, IS (0,3μM), ODQ, UGN (0,3μM), BK (0,9 ou 0,3nM) não interferiram significativamente na pressão de perfusão, na diurese ou na reabsorção tubular fracionada renal de eletrólitos (sódio - %TNa+; potássio - %TK+; cloreto - %TCl-). Nas condições experimentais, ODQ mostrou-se eficaz (p < 0,05) em inibir os efeitos de BK (1,8nM) sobre a pressão de perfusão (ODQ+BK120min: 111+-3mmHg; BK12min: 139+-5mmHg) e %TNa+ (ODQ+BK120min: 80+-1%; BK120min: 76+-2%). IS (3μM) mostrou-se parcialmente eficaz em inibir efeitos de UGN (0,6μM; IS+UGN90min: 76+-2%; UGN90min: 72+-2%) e de BK (1,8nM; IS+BK90min: 81+-2%; BK60min: 0,76+-2%) sobre %TNa+. UD (0,03nM90min: 86+-2%; UGN+UD90min: 73+-4%; p < 0,05) potencializou a natriurese produzida por UGN (0,3μM90min: 83+-2%), cujos efeitos vasculares foram inibidos com BK (0,3nM90min: 104+-5mmHg; UGN0,6μM 90min: 135+-4mmHg; UGN+BK90min: 110+-2mmHg). Conclusões: IS e ODQ comprovaram a participação da via de sinalização NO-GMP no mecanismo de ação dos peptídeos estudados. A perfusão simultânea com mais de um peptídio, comprovou que há interações em suas diferentes vias de sinalização...

Papel de las proteínas G heterotriméricas sensibles a mastoparán en la activación muscarínica del músculo liso de vías aéreas / Paper of heterotrimetric G-proteins sensitive to mastoparan in the muscarinic activation of tracheal smooth muscle

La activación muscarínica del músculo liso traqueal de bovino (MLTB) genera de dos señales de GMPc (20 y 60s), la primera atribuida a la Guanililciclasa soluble (sGC) y la segunda a la Guanililciclasa particulada (NPR-GC). Existen evidencias que la activación muscarínica es mediada. En este sentido determinamos el efecto del tetradecapéptido desacoplante de las proteínas G Mastoparán sobre dicha activación, evaluando los niveles de GMPc y la actividad contráctil del MLTB. Mastoparán inhibió en un 63 por ciento la primera señal de GMPc y desapareció la segunda. Posteriormente evaluamos el efecto de Mastoparán sobre las sGC y NPR-GC. La enzima sGG se evalúo utilizando el Nitroprusiato de Sodio (SNP), el cual indujo un patrón bifásico de acumulación GMPc, las NPR-GC, fueron evaluadas utilizando los péptidos natriuréticos ANP y CNP-53 los cuales indujeron patrones monotónico y bifásicos respectivamente. Observando en los tres casos que la preincubación con Mastoparán, disminuyó los niveles de GMPc de manera significativa (p<0.05). Dicho efecto fue atribuido a proteínas Gi ya que al pre-tratar el MLTB con PTX desaparecía el efecto de Mastoparán. También evaluamos la actividad contráctil del MLTB, encontrándose que Mastoparán se comportan como un "inhibidor no competitivo" de la contracción muscarínica, sin comprometer la integridad funcional de la maquinaria contráctil ya que las aminas biogenas histamina y serotonina produjeron potentes contracciones. Estos hallazgos nos sugieren que la inhibición selectiva de las señales de GMPc esta relacionada con el bloqueo de la contracción muscarínica.

Neuroendocrine control of body fluid homeostasis

Angiotensin II and atrial natriuretic peptide (ANP) play important and opposite roles in the control of water and salt intake, with angiotensin II promoting the intake of both and ANP inhibiting the intake of both. Following blood volume expansion, baroreceptor input to the brainstem induces the release of ANP within the hypothalamus that releases oxytocin (OT) that acts on its receptors in the heart to cause the release of ANP. ANP activates guanylyl cyclase that converts guanosine triphosphate into cyclic guanosine monophosphate (cGMP). cGMP activates protein kinase G that reduces heart rate and force of contraction, decreasing cardiac output. ANP acts similarly to induce vasodilation. The intrinsic OT system in the heart and vascular system augments the effects of circulating OT to cause a rapid reduction in effective circulating blood volume. Furthermore, natriuresis is rapidly induced by the action of ANP on its tubular guanylyl cyclase receptors, resulting in the production of cGMP that closes Na+ channels. The OT released by volume expansion also acts on its tubular receptors to activate nitric oxide synthase. The nitric oxide released activates guanylyl cyclase leading to the production of cGMP that also closes Na+ channels, thereby augmenting the natriuretic effect of ANP. The natriuresis induced by cGMP finally causes blood volume to return to normal. At the same time, the ANP released acts centrally to decrease water and salt intake

Efecto de la toxina pertussis sobre la actividad guanilil ciclasa dependiente de Mg²+ en el músculo liso traqueal de bovino / Effect of the pertussis toxins on the guanylate cyclase dependent activity of Mg² + in the tracheal musde smooth of bovine

Las membranas plasmáticas de músculo liso traqueal de bovino presentan una actividad de guanililciclasa dependiente de Mg²+, determinada utilizando radioinmunoensayo para GMPc, sobre la cual se estudió el efecto de la toxina pertussis. Se observó un comportamiento bimodal dependiente de la concentración de Mg²+: efecto estimulatorio hasta una concentración de Mg²+ 2mM y efecto inhibitorio a concentraciones mayores del ión. El agonista carbamilcolina también mostró un efecto dual sobre esta actividad enzimática: estimulatorio hasta 10-9 M e inhibitorio a concentraciones mayores. La toxina pertussis produce un efecto bloqueador de la guanililciclasa dependiente de Mg²+ y eso permite concluir que dicha actividad es modulada por proteína Go/Gi en forma similar a lo descrito previamente para la actividad guanililciclasa dependiente de Mn²+ en la misma fracción de membranas, pero en el caso de la actividad dependiente de Mg²+, aparentemente se requiere del componente inhibitorio de la proteína G para ejercer su función

Presencia de guanilil ciclasas sensibles a los péptidos natriuréticos ANP y CNP en el músculo liso traqueal de bovino / Guanylyl cyclases sensibility to natriuretic peptide ANP and CNP in the tracheal muscle smooth of bovine

La producción de GMP cíclico en el músculo liso traqueobronquial de bovino (MLTB) es catalizada por guanilil ciclasas soluble (sGC) y particulada (mGC). Para la identificación de la mGC involucrada en la regulación muscarínica, via receptores M2 y M3 del tono de MTLB, se amplificó a partir de cDNA obtenido del MLTB una región conservada en el dominio catalítico de todas las GC. La secuenciación de los productos de RT-PCR reveló que el 76 por ciento de los transcriptos codifican para la subunidad ß1 de sGC y el 24 por ciento para la isoforma B (sensible al péptido CNP) de la mGc. RT-PCRs con oligonucléotidos isoforma-específicos mostraron que las isoformas sensibles a los péptidos ANP y guanilina también se expresan en el MLTB. La activación máxima de mGC obtenida con CNP resultó significativamente (p<0.001) superior a la lograda con ANP, indicando que la isoforma B es la mGC predominante en este tejido

Rol del óxido nítrico en la apoptosis del megacariocito / Nitric oxide role in megakaryocyte apoptosis

El óxido nítrico es uno de los metabolitos más pequeños biológicamente activo que regula distintos procesos fisiológicos y patofisiológicos en el sistema cardiovascular, inmune y nervioso. Hemos explorado recientemente su rol en la megacariocitopoyesis utilizando como modelo in-vitro el cultivo líquido de células mononucleares o de células indiferenciadas obtenidas a partir de médula ósea humana y estimuladas con trombopoyetina. Se observó que la generación de óxido nítrico de manera exógena es capaz de inhibir el crecimiento de los megacariocitos induciendo apoptosis tanto en células de estadios inmaduros como terminales por un mecanismo independiente de la guanilil ciclasa. La exposición de los cultivos a la L-arginina (sustrato fisiológico) o a una combinación de citoquinas proinflamatorias resultó en una supresión del crecimiento de los megacariocitos junto con un aumento significativo en los niveles de óxido nítrico. La presencia de inhibidores de la síntesis de óxido nítrico bloqueó su producción y revirtió parcialmente la inhibición del crecimiento de los megacariocitos. Nuestros resultados constituyen la primera evidencia de que el óxido nítrico inhibe el crecimiento de megacariocitos por inducción de apoptosis. Este hallazgo presenta nuevas perspectivas para comprender los fenómenos involucrados en la megacariocitopoyesis y en la formación de plaquetas.