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

Soluble guanylate cyclase stimulators:research advances / 国际药学研究杂志

The soluble guanylate cyclase (s GC) is a key signal transduction enzyme in the nitric oxide (NO) -sGC-cyclic guanosine monophosphate (cGMP) pathway, which can be activated by NO and thus catalyzes the conversion of guanosine triphosphate (GTP) into the c GMP. As a second messenger, cGMP modulates the activity of downstream effectors, including the cGMP-dependent protein kinases (cGK), cGMP-dependent phosphodiesterases (PDE) and ion-gated channels, and ultimately participates in the regulation of several physiological functions, including the function of cardiovascular, gastrointestinal and central nervous systems. sGC stimulators could not only directly stimulate s GC but also synergistically act with NO to increase the sGC enzyme activity, which has shown a great potential to treat various diseases via regulating the NO-s GC-cGMP signaling pathway. Here, we give an overview of NOindependent sGC stimulators in clinical trial.

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...

Advances in soluble guanylate cyclase stimulator / 中国药科大学学报

@#Soluble guanylate cyclase is a key signal transduction enzyme in the body, which can activate the NO-sGC-cGMP signaling pathway and inhibit the TGF-β signaling pathway. cGMP is one of the most important second messengers and also involved in a series of physiological or pathological responses including vasodilation, inhibition of platelet aggregation, inhibition of cell proliferation and so on. When TGF-β signaling pathway is inhibited, it can inhibit issue fibrosis and cell proliferation. Recent studies have shown that sGC can be activated directly to treat a variety of diseases. As a new class of potential drugs, sGC stimulators have shown many unique advantages. Herein, the mechanism and the latest research progress of sGC stimulators are reviewed, which could provide a useful information for further research of sGC stimulators.

Progress in Research on Guanylyl Cyclase C in Diagnosis and Treatment of Colorectal Cancer / 胃肠病学

Guanylyl cyclase C( GCC)is a specific intestinal tissue polypeptide expressed in intestinal epithelial cells,and is also expressed in colorectal cancer cell line and primary and metastatic colorectal cancer. Studies have indicated that level of GCC mRNA in blood could contribute to the early detection of colorectal cancer metastasis and recurrence,and is beneficial to the formulation of therapeutic regimen and follow-up. This article reviewed the progress in research on GCC in diagnosis and treatment of colorectal cancer.

Effect of novel agonist of soluble guanylate cyclase sGC 003 on endothelin-1-induced cardiomyocyte hypertrophy / 中国药理学与毒理学杂志

OBJECTIVE To investigate the protective effect of sGC003,a novel agonist of soluble guanylate cyclase,on endothelin-1(ET-1)-induced cardiomyocyte hypertrophy. METHODS Cardiomy?ocytes were isolated from neonatal Sprague-Dawley rats using serial enzymatic digestion and then incubated with ET-1 10 nmol·L-1 in the absence or presence of sGC003 0.01,0.1 and 1.0μmol·L-1. Hyper?trophic responses including the cardiomyocyte area(Image-Pro Plus 6.0),the expression of atrial natri?uretic peptide gene(ANP)mRNA(RT-PCR method)and total protein content(BCA method)were detect?ed. RESULTS After 48 h stimulation with ET-1 10 nmol·L-1,the cardiomyocyte area increased by 80%(P<0.01),the total protein content increased by 120%(P<0.01) and the expression of ANP mRNA up-regulated by 140%(P<0.01). sGC003 0.01,0.1 and 1.0μmol · L-1 elicited antihypertrophic actions, including inhibition of ET-1-mediated increase in the cardiomyocyte area(P<0.01),raised total protein content(P<0.05)and upregulation of ANP mRNA(P<0.05). CONCLUSION sGC003 has protective,car?diomyocyte-selective antihypertrophic effects in vitro.

Correlation of preoperative guanylate cyclase C mRNA in peripheral blood with postoperative gastric cancer recurrence / 第二军医大学学报

Objective To explore the correlation of preoperative guanylate cyclase C (GC-C) mRNA in peripheral blood with postoperative gastric cancer recurrence. Methods The preoperative blood samples were collected from 60 patients with gastric cancer (GC) before operation, also from 21 patients with dysplasia, 15 with intestinal metaplasia, and 20 healthy volunteers during the same period. GC-C mRNA in the peripheral blood samples was assessed by real-time fluorescent quantitative PCR (RFQ-PCR). The association of peripheral blood GC-C mRNA expression with pathological parameters and gastric cancer recurrence was analyzed. Results The positive rate of preoperative GC-C mRNA in blood samples of gastric cancer patients (48. 3% [29/60]) was significantly higher than that of patients with dysplasia (20. 0%[3/21], P

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.

Linaclotide: a guanylate cyclase agonist for treatment of irritable bowel syndrome with constipation and chronic constipation in adults.

Linaclotide, a 14 aminoacid peptide is an intestinal secretagogue and works by stimulating guanylate cyclase (GC-C) present in the intestinal epithelium, which leads to improvement in symptoms of irritable bowel syndrome with constipation and chronic constipation in adults. Treatments available currently for these gastrointestinal problems have not been very satisfactory and many new options are therefore being explored to provide relief to these patients. Linaclotide has shown promising results in various clinical trials and hence was approved by US Food and Drug Administration (FDA) in 2012.

Investigation of seizure activity after cyclic nucleotide phosphodiesterase inhibition with second messenger and calcium ion channel inhibition in mice.

The role of PDE-4 inhibitor etazolate, was evaluated in the presence of PDE-7 inhibitor, BRL-50481, in animal models of epilepsy. Seizures were induced in the animals by subjecting them to injection of chemical convulsants, Pilocarpine, Kainic acid (KA) and maximal electroshock (MES). The combination of etazolate and BRL50481 treated mice showed a significant (P<0.001) quick onset of action, jerky movements and convulsion when compared to gabapentin. The combination of etazolate and sGC inhibitor, methylene blue (MB) treated mice showed a significant (P<0.001) delay in onset of action, jerky movements and convulsion when compare to gabapentin as well as against the combination of etazolate with BRL 50481.The present study mainly highlights the individual effects of etazolate and combination with BRL-50481 potentiates (P<0.001) the onset of seizure activity against all models of convulsion. The study mainly comprises the onset of seizures, mortality/recovery, percentage of prevention of seizures (anticonvulsant) and total duration of convulsive time. The total convulsive time was prolonged significantly (P<0.05 and P<0.01) in combination of methylene blue with etazolate treated (28.59% and 35.15 %) groups, compared to DMSO received group (100%) in the MES model. In the same way, the combination of calcium channel modulator (CCM) and calcium channel blocker (CCB) amiodarone and nifedipine respectively, with etazolate showed a significant (P<0.001) delay in onset of seizures, compared to DMSO and etazolate treated groups in all models of epilepsy. This confirms that both CCM and CCB possess anticonvulsant activity. Finally, the study reveals that identification of new cAMP mediated phosphodiesterases family members offers a potential new therapy for epilepsy management in future.

Methylene blue administration in the compound 48/80-induced anaphylactic shock: hemodynamic study in pigs / Administração de azul de metileno no choque anafilático induzido por composto 48/80: estudo hemodinâmico em suínos

PURPOSE: To verify if the methylene blue (MB) administration prevents and/or reverses the compound 48/80 (C48/80)-induced anaphylactic shock in pigs. METHODS: Female Dalland pigs were anesthetized and had the hemodynamic parameters recorded during the necessary time to administer some drugs and observe their effect. The animals were randomly assigned to one of the five groups: 1) control; 2) MB: the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 3) C48/80: the animals received a bolus injection of C48/80 (4 mg/kg); 4) C48/80+MB: the animals received a bolus injection of C48/80 (4 mg/kg) and 10 minutes after the C48/80 administration the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 5) MB+C48/80: the animals received a bolus injection of MB (2 mg/kg) and 3 minutes later they received a bolus injection of C48/80 (4 mg/kg). RESULTS: The intravenous infusion of MB alone caused no changes in the mean arterial pressure (MAP) showing that the administered MB dose was safe in this experimental model. The C48/80 was effective in producing experimental anaphylactic shock since it was observed a decrease in both MAP and cardiac output (CO) after its administration. The MB did not prevent or reverse the C48/80-induced anaphylactic shock in this model. In fact, the MAP of the animals with anaphylactic shock treated with MB decreased even more than the MAP of the animals from the C48/80 group. On the other hand, the C48/80-induced epidermal alterations disappeared after the MB infusion. CONCLUSION: Despite our data, the clinical manifestations improvement brings some optimism and does not allow excluding the MB as a possible therapeutic option in the anaphylactic shock.

OBJETIVO: Verificar se a administração de azul de metileno (AM) previne e/ou reverte o choque anafilático induzido por composto 48/80 (C48/80) em suínos. MÉTODOS: Porcos fêmeas Dalland foram anestesiados e tiveram os parâmetros hemodinâmicos registados durante o tempo necessário para administrar algumas drogas e observar seu efeito. Os animais foram aleatoriamente destribuídos em um dos cinco grupos: 1) controle, 2) AM: os animais receberam uma injeção em bolus de AM (2mg/kg), seguido de infusão contínua de AM (2,66mg/Kg /h por bomba de infusão de seringa); 3) C48/80: os animais receberam uma injeção em bolus de C48/80 (4mg/kg); 4) C48/80 + AM: os animais receberam uma injeção em bolus de C48/80 (4mg/kg) e 10 minutos após a administração de C48/80 os animais receberam uma injeção em bolus de AM (2mg/kg), seguido de infusão contínua de AM (2,66mg/kg/h por bomba de infusão de seringa); 5) AM+C48/80: os animais receberam uma injeção em bolus de AM (2mg/kg) e três minutos depois, receberam uma injeção em bolus de C48/80 (4mg/kg). RESULTADOS: A infusão intravenosa de AM não causou mudanças na pressão arterial média (PAM), mostrando que a dose de AM administrada foi segura neste modelo experimental. O C48/80 foi eficaz na indução do choque anafilático experimental, uma vez que foi observada redução na PAM e débito cardíaco (DC), após a sua administração. O AM não preveniu ou reverte o choque anafilático induzido por C48/80 neste modelo. Na verdade, a PAM dos animais com choque anafilático tratados com AM diminuiu mais do que o PAM dos animais do grupo C48/80. Por outro lado, as alterações epidérmicas induzidas pelo C48/80 desapareceu após a infusão do AM. CONCLUSÃO: Apesar dos resultados a melhora clínica das manifestações anafiláticas permite considerar a possibilidade do azul de metileno como opção terapêutica no tratamento do choque anafilático.

Administração de BAY 41-2272 previne disfunção vesical em ratos deficientes de oxido nítrico / Administration of BAY 41-2272 prevents bladder dysfunction in nitric-oxide deficient rats

Objective: to evaluate the protective effects of BAY 41-2272, a soluble guanylate cyclase activator, on changes in cystometric parameters in rats deficient in nitric oxide (NO). Methods: Rats were divided into the following groups: (a) control; (b) DMSO; (c) L-NAME; (d) BAY 41-2272 alone; (e) L-NAME + BAY 41-2272. The NO synthase blocker L-NAME (20 mg/rat/day) was given in drinking water concomitantly or not with BAY 41-2272 (10 mg/kg/day, given by gavage). Results: Chronic L-NAME treatment markedly increased the mean arterial blood pressure, and co-treatment with BAY 41-2272 nearly reversed L-NAME-induced rise on mean arterial blood pressure. Non-void contractions were significantly increased in L-NAME group (0.90 ± 0.1 number/minute) compared with either DMSO or control group (0.49 ± 0.1 number/minute), which were prevented by co-treatment with BAY 41-2272 (0.56 ± 025 number/minute; p < 0.05). The threshold and peak pressure increased by 70 and 44%, respectively, after chronic L-NAME treatment, while co-treatment with BAY 41-2272 largely attenuated both effects (27 and 22% increase, respectively). The frequency of micturition cycles decreased by about of 50% in L-NAME-treated rats compared with control animals, and co-treatment with BAY 41-2272 normalized this parameter. Conclusions: Our data show that long-term oral administration of BAY 41-2272 counteracts the bladder dysfunction seen in NO-deficient rats, indicating that restoration of the NO-cGMP pathway by this compound may be of beneficial value to treat bladder symptoms.

Objetivo: avaliar os efeitos protetores do BAY 41-2272, um ativador solúvel da guanilato ciclase, sobre alteração dos parâmetros citométricos em ratos deficientes de óxido nítrico (NO). Métodos: os ratos foram divididos nos seguintes grupos: (a) controle; (b) DMSO (c) L-NAME; (d) BAY 41-2272 isolado; (e) L-NAME + BAY 41-2272. O bloqueador da NO-sintase L-NAME (20 mg/rato/dia) foi ministrado na água de beber, concomitantemente ou não com o BAY 41-2272 (10 mg/kg/dia, ministrado por gavagem). Resultados: o tratamento crônico com L-NAME aumentou de forma acentuada a pressão arterial média, e o co-tratamento com BAY 41-2272 quase reverteu o aumento na pressão arterial média induzido por L-NAME. Contrações não esvaziadoras da bexiga mostraram-se significativamente aumentadas no grupo L-NAME (0,90 ± 0,1 número/minuto) comparadas com DMSO ou grupo controle (0,49 ± 0,1 número/minuto), que foram evitadas pelo co-tratamento com BAY 41-2272 (0,56 ± 0,25 número/minuto; p < 0,05). O limiar e o pico de pressão aumentaram em 70 e 44%, respectivamente, após o tratamento crônico com L-NAME, enquanto o co-tratamento com BAY 41-2272 atenuou muito ambos os efeitos (27 e 22% de aumento, respectivamente). A frequência de ciclos de micção diminuiu em 50% nos ratos tratados com L-NAME em comparação aos animais controle; o cotratamento com BAY 41-2272 normalizou esse parâmetro. Conclusões: nossos dados mostram que a administração oral a longo prazo de BAY 41-2272 contrapõe-se à disfunção de bexiga vista em ratos deficientes de NO, o que sugere que a restauração da via da NO-cGMP por esse composto pode ter valor benéfico para tratar sintomas vesicais.

Diagnosis and treatment of guanylyl cyclase-C and colorectal cancer / 国际肿瘤学杂志

Guanylyl cyelase-C (GC-C) is recently reported as the intestinal specific polypeptide receptor,which is expressed selectively by cells from intestinal mucosa,including normal intestinal cells,primary and metastatic colorectal cancer cells.Stimulated by heat-stable enterotoxin (STa),guanylin and uroguanylin,GC-C could not only regulate the proliferation and differentiation of intestinal cells,but also inhibit the proliferation of colorectal cancer cells and DNA synthesis.Micrometastases of the colorectal cancer can be found in lymph nodes,peripheral blood and liver lobes by GC-C detection.We can also perform GC-C and ligands for targeted prevention and therapy of colorectal cancer.GCC play important roles in detecting occult micrometastasos of colorectal cancer and targeted therapy.

Curcumin ameliorates high glucose-induced dysfunction of vasoconstriction via heme oxygenase-1 and GC pathway / 中国病理生理杂志

AIM: To explore the protective effect of curcumin on high glucose-induced decrease in contraction of isolated rat aortic rings, and to elucidate its underlying mechanism. METHODS: The thoracic aortic rings with endothelium of male Sprague-Dawley rats were mounted on a bath system. Isometric contractions of aortic rings were measured. HO activity was also evaluated. RESULTS: (1)Four hours after incubated with 44 mmol/L of glucose (high glucose),the vascular contraction responses to phenylephrine (PE) decreased compared to control group (containing 11 mmol/L of glucose). (2)Coincubation with curcumin (3×10~(-11)-3×10~(-10) mol/L) and high glucose,the high glucose-induced decrease in contraction responses to PE of arteries was partly inhibited. (3)Four hours after incubation with curcumin,the HO activity in thoracic aorta increased. ZnPP,an inhibitor of HO-1,completely abrogated the protection effect of curcumin. (4)Methylene blue,an inhibitor of guanylate cyclase (GC),partly abolished the protective effect of curcumin. CONCLUSION: Curcumin prevents the high glucose-induced decrease in contraction responses to PE in intact aortic rings. The mechanism might be mainly involved in the activation of HO-1 and GC.

Inhibition of Hypoxic Pulmonary Vasoconstriction of Rats by Carbon Monoxide

Hypoxic pulmonary vasoconstriction (HPV), a unique response of pulmonary circulation, is critical to prevent hypoxemia under local hypoventilation. Hypoxic inhibition of K+ channel is known as an important O2-sensing mechanism in HPV. Carbon monoxide (CO) is suggested as a positive regulator of Ca2+-activated K+ channel (BK(Ca)), a stimulator of guanylate cyclase, and an O2-mimetic agent in heme moiety-dependent O2 sensing mechanisms. Here we compared the effects of CO on the HPV (Po2, 3%) in isolated pulmonary artery (HPV(PA)) and in blood-perfused/ventilated lungs (HPV(lung)) of rats. A pretreatment with CO (3%) abolished the HPV(PA) in a reversible manner. The inhibition of HPV(PA) was completely reversed by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), a guanylate cyclase inhibitor. In contrast, the HPV(lung) was only partly decreased by CO. Moreover, the partial inhibition of HPV(lung) by CO was affected neither by the pretreatment with ODQ nor by NO synthase inhibitor (L-NAME). The CO-induced inhibitions of HPV(PA) and HPV(lung) were commonly unaffected by tetraethylammonium (TEA, 2 mM), a blocker of BK(Ca). As a whole, CO inhibits HPV(PA) via activating guanylate cyclase. The inconsistent effects of ODQ on HPV(PA) and HPV(lung) suggest that ODQ may lose its sGC inhibitory action when applied to the blood-containing perfusate.

Methylene blue for clinical anaphylaxis treatment: a case report

CONTEXT AND OBJECTIVE: Nitric oxide has a pathophysiological role in modulating systemic changes associated with anaphylaxis. Nitric oxide synthase inhibitors may exacerbate bronchospasm in anaphylaxis and worsen clinical conditions, with limited roles in anaphylactic shock treatment. The aim here was to report an anaphylaxis case (not anaphylactic shock), reversed by methylene blue (MB), a guanylyl cyclase inhibitor. CASE REPORT: A 23-year-old female suddenly presented urticaria and pruritus, initially on her face and arms, then over her whole body. Oral antihistamine was administered initially, but without improvement in symptoms and signs until intravenous methylprednisolone 500 mg. Recurrence occurred after two hours, plus vomiting. Associated upper respiratory distress, pulmonary sibilance, laryngeal stridor and facial angioedema (including erythema and lip edema) marked the evolution. At sites with severe pruritus, petechial lesions were observed. The clinical situation worsened, with dyspnea, tachypnea, peroral cyanosis, laryngeal edema with severe expiratory dyspnea and deepening unconsciousness. Conventional treatment was ineffective. Intubation and ventilatory support were then considered, because of severe hypoventilation. But, before doing that, based on our previous experience, 1.5 mg/kg (120 mg) bolus of 4 percent MB was infused, followed by one hour of continuous infusion of another 120 mg diluted in dextrose 5 percent in water. Following the initial intravenous MB dose, the clinical situation reversed completely in less than 20 minutes, thereby avoiding tracheal intubation. CONCLUSION: Although the nitric oxide hypothesis for MB effectiveness discussed here remains unproven, our intention was to share our accumulated cohort experience, which strongly suggests MB is a lifesaving treatment for anaphylactic shock and/or anaphylaxis and other vasoplegic conditions.

CONTEXTO E OBJETIVO: O óxido nítrico (NO) tem papel fisiopatológico na modulação das alterações sistêmicas associadas à anafilaxia. Inibidores da sintase do NO podem exacerbar a broncoconstrição na anafilaxia e piorar as condições clínicas e têm um papel limitado no tratamento do choque anafilático. O objetivo deste relato foi o de apresentar um caso de anafilaxia (não-choque anafilático) revertido pela inibição da guanilato ciclase pelo azul de metileno. RELATO DE CASO: Mulher de 23 anos apresentou repentina urticária e prurido, inicialmente localizados na face e nos braços, que se estenderam para quase todo o corpo. Utilizou-se, inicialmente, anti-histamínico, mas pequena melhora só foi observada após o uso endovenoso de 500 mg metilprednisolona. Após duas horas, os sintomas voltaram acompanhados de vômitos. Observou-se dificuldade respiratória alta, sibilos respiratórios, estridores laríngeos, angioedema facial, incluindo eritema, edema de lábios e, nos locais de intenso prurido, observaram-se petéquias. O quadro agravou-se com dispnéia, taquipnéia, parestesia peroral, edema laríngeo, grave dispnéia expiratória com crescente perda da consciência. O tratamento convencional não foi efetivo. Considerou-se intubação pela grave hipoventilação. Com base em nossa prévia experiência, um bolo endovenoso de 1,5 mg/kg (120 mg) de azul de metileno a 4 por cento diluído em soro glicosado 5 por cento, seguido de outros 120 mg infundidos durante uma hora. Após a dose endovenosa inicial do azul de metileno, a situação clínica reverteu-se completamente, evitando-se a intubação traqueal. CONCLUSÃO: Embora a hipótese da eficácia da relação entre o óxido nítrico e o azul de metileno ainda esteja por ser provada, nossa intenção foi de compartilhar nossa experiência acumulada, que sugere fortemente que o azul de metileno seja um tratamento salvador de vidas para o choque anafilático e/ou anafilaxia e outras condições vasoplégicas.

Early Reversible Changes on ERG in Pharmaceutically Induced Retinal Degeneration in Rats

PURPOSE: To evaluate the early ERG (electroretinogram) changes in N-methyl-N-nitrosourea (MNU)-induced retinal degeneration in rats. METHODS: Thirty-six 6-week-old male rats were injected intraperitoneally with 60mg/kg MNU and divided into 6 groups. Histology and ERG were recorded for the rats of each group before treatment and at 3, 6, 12, 18, and 24 hours after MNU injection. Promptly after the ERG recording, rats were sacrificed and the eyeballs prepared for histologic sectioning. The Tdt-mediated dUTP-digoxigenin nick end labeling (TUNEL) method was used to detect photoreceptor cell death. RESULTS: The first decreases of ERG responses were noticed maximally at 3 hours after the treatment. Thereafter, the amplitude of the responses was partially recovered at 12 hours post-treatment. The second decrease of ERG amplitudes was observed in the 18-hour recordings, and those changes progressed to 24 hours after the treatment. In the histologic findings, TUNEL (+) cells in the Outer Nuclear Layer (ONL) were not detected at 3 hours after MNU injection, but were initially noticed at 6 hours post-injection. CONCLUSIONS: The first decreases of ERG amplitudes proceeded the appearance of TUNEL (+) cells in ONL, and these electrophysiological changes seemed to not be related to photoreceptor cell death. We propose that electrophysiological changes observed might be related to the MNU-induced activity enhancement of guanylate cyclase in the phototransduction pathway. We also show that photoreceptor cell death in the MNU-induced retinal degeneration model occurs at 6 hours after the treatment, which is earlier than the results of previous reports.

The Effects of Methylene Blue on Hemodynamic Parameters and Cytokine Levels in Refractory Septic Shock

BACKGROUND: Endogenous nitric oxide (NO) induces the peripheral vasodilation via the activation of guanylate cyclase in patients with septic shock. The purpose of this study was to assess the acute effects of methylene blue (MB), which is an inhibitor of guanylate cyclase, on the hemodynamics and on the production of pro-inflammatory cytokines and nitric oxide (NO) in patients with refractory septic shock. METHODS: Twenty consecutive patients with refractory septic shock, which was defined as shock refractory to a dopamine infusion of more than 20 microgram/kg/min with the appropriate use of antibiotics and adequate volume replacement, received MB infusion of 1 mg/kg intravenously. The hemodynamic and respiratory variables were measured at baseline, 30, 60 and 120 min after an infusion of MB (1 mg/kg). The blood levels of NO, IL-1, IL-10 and TNF-alpha were measured at baseline, 30 and 120 min after MB infusion. RESULTS: The administration of MB induced an increase in the systemic vascular resistance (SVR) that resulted in an increase of the mean arterial pressure (MAP) in patients with refractory septic shock, and this was without a decrease in cardiac output. The administered MB induced an increase in pulmonary vascular resistance (PVR) that resulted in an increase of pulmonary arterial pressure (PAP), without any deterioration of gas exchange. However, the increases in SVR and PVR were not associated with the alteration of endogenous production of NO, IL-1, IL-10 and TNF-alpha. CONCLUSION: MB transiently elevated the MAP by increasing the SVR without altering the endogenous productions of NO, IL-1, IL-10 and TNF-alpha during the study period in patients with refractory septic shock.

Research progress in guanylin family / 中国病理生理杂志

Guanylin family, described in recent 10 years, is a series of small peptides (including guanylin, uroguanylin and lymphoguanylin) with structural and functional similarities to heat-stable enterotoxins (STs) elaborated by various pathogenic bacteria. They are abundance of cysteines and are endogenous activators of guanylyl cyclase-C (GC-C) receptors. Immunoreactive guanylin family peptides are localized in many human organs and tissues, especially in gastrointestinal tract and kidney, and play an important role in regulation of water and salt homeostasis. Recent studies showed that the mRNA levels of guanylin family peptides were down-regulated in colorectal cancers; oral intake of uroguanylin might suppress polyp formation in Apc(Min/+) mouse, and ~(111)In-labeled-ST peptide analog might specifically target human colon cancers. These evidences highlight that guanylin family may have a potential application in diagnosis and therapy effects of colorectal cancers.

Effects of hypoxia and hypercapnia on expression of soluble guanylate cyclase in rat pulmonary artery / 中国病理生理杂志

AIM: To investigate the expression of soluble guanylate cyclase protein and its mRNA in rat pulmonary artery after exposure to hypoxia and hypercapnia. METHODS: Male Sprague-Dawley rats were randomly split into 4 group, which were hypoxic hypercapnic (HH 1 week, HH 2 weeks, HH 4 weeks) group and control group, to copy pulmonary hypertensive animal model. The expression of sGC? 1 and ? 1 subunits protein of medial and small pulmonary artery was performed by immunohistochemistry with a polycolonal antibody. In situ hybridization was performed on the rat lung tissue using sGC oligonuclear probe to assay the expression of sGC? 1 subunit mRNA. RESULTS: The sGC? 1 and ? 1 subunits protein and sGC? 1 subunit mRNA were faint staining in the pulmonary small and medium artery in HH1 week, HH 2 weeks and HH 4 weeks groups compared with control group (all P