RESUMO
Rosuvastatin was tested on rat aortic rings in the presence and absence of K(+) channel blockers, mevalonic acid, and inhibitors of nitric oxide, prostaglandins, or endothelial-derived hyperpolarizing factor synthesis. The direct vascular effects of rosuvastatin were then evaluated by obtaining dose-response curves. Rosuvastatin relaxed aortic rings with and, to a lesser degree, without endothelium. Under both these conditions this effect was partially inhibited by L-NAME, tetraethylammonium, apamin + charybdotoxin (only administered together), or mevalonic acid. The combination of L-NAME with any of the other 3 treatments completely inhibited the effect of rosuvastatin, but indomethacin, clotrimazol, glibenclamide, charybdotoxin, or apamin alone had no effect. Therefore, the relaxation induced by rosuvastatin, even in the absence of endothelium, is partially related to 2 different mechanisms, one that is isoprenoid dependent and NO mediated and the other that is tied to the opening of Ca( 2+)-dependent K(+) channels of the slow subfamily.
Assuntos
Aorta Torácica/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Fluorbenzenos/farmacologia , Canais de Potássio Cálcio-Ativados/efeitos dos fármacos , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Animais , Aorta Torácica/enzimologia , Aorta Torácica/metabolismo , Fatores Biológicos/metabolismo , Inibidores de Ciclo-Oxigenase/farmacologia , Relação Dose-Resposta a Droga , Endotélio Vascular/enzimologia , Endotélio Vascular/metabolismo , Técnicas In Vitro , Masculino , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Cálcio-Ativados/metabolismo , Prostaglandinas/metabolismo , Ratos , Ratos Wistar , Rosuvastatina CálcicaRESUMO
In this study we evaluate the effects of alpha-tocopherol on the metabolic control and oxidative stress in female patients with type 2 diabetes mellitus. Thirty-four female type 2 diabetics 40-70 years old up to 14 years with diabetes, under medical treatment, were randomly divided in two groups. One group received placebo (Control group, n = 21) and the other received alpha-tocopherol (800 IU/day, n = 13) during 6 weeks. Blood samples were collected at the beginning and at the end of the study to measure malondialdehyde production, glycated hemoglobin, selenium dependent-glutathione peroxidase, Cu,Zn-superoxide dismutase in erythrocytes and total antioxidant status, glucose, lipid and lipoproteins in serum. Erythrocyte malondialdehyde decreased and serum-total antioxidant status increased after alpha-tocopherol treatment (P < 0.0001). However, an unexpected increase on cholesterol levels and a reduced erythrocyte-Cu,Zn-superoxide dismutase activity was observed after alpha-tocopherol treatment. alpha-Tocopherol administration did not affect glucose, glycated hemoglobin, triacylglycerides, lipoprotein levels and serum malondialdehyde. A minor oxidative stress was observed in female type 2 diabetic patients after alpha-tocopherol treatment inferred from the reduced levels of erythrocyte malondialdehyde and the increased values of total antioxidant status. On the other hand, no beneficial changes were observed on glycemic control or lipid metabolism.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , alfa-Tocoferol/análogos & derivados , Adulto , Idoso , Antioxidantes/administração & dosagem , Antioxidantes/uso terapêutico , Cápsulas , LDL-Colesterol/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/metabolismo , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Feminino , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/sangue , Pessoa de Meia-Idade , Superóxido Dismutase/sangue , Fatores de Tempo , Tocoferóis , alfa-Tocoferol/administração & dosagem , alfa-Tocoferol/uso terapêuticoRESUMO
Los quimiorreceptores son estructuras específicas ampliamente distribuidas en el organismo. El cuerpo carotídeo es el representante principal de este sistema, por lo que es el mejor estudiado y sirve de punto de comparación para el conocimiento de otros quimiorreceptores. El quimiorreceptor ciliar ha sido identificado únicamente en aves, pero su estructura no ha sido descrita en detalle. Este trabajo representa una breve comunicación preliminar.
