RESUMO
The mechanisms involved in the cardioprotector effect of red wine have not yet been completely elucidated but probably an endothelium-dependent vasodilator action may play a significant role in this effect. Experiments were undertaken to determine whether a Brazilian red wine (BRW) induces vasodilation in the mesenteric vascular bed (MVB) and an antihypertensive effect was also assessed in rats with NO-deficient hypertension. In MVB precontracted with norepinephrine, BRW (alcohol-free lyophilized) induces a long-lasting endothelium-dependent vasodilation that is not reduced by indomethacin. Inhibition of NO-synthase by NG-nitro-L-arginine methyl ester (L-NAME) and guanylyl cyclase by 1H-[1,2,3] oxadiazolo [4,4-a]quinoxalin-1-one (ODQ) reduces the vasodilator effect of BRW. In vessels precontracted with norepinephrine and depolarized with KCl (25 Mm) or treated with Ca-dependent K channel blockers charybdotoxin (ChTx) plus apamin, the effect of BRW was significantly reduced. However, this effect is not affected by ATP-dependent K (KATP) channel blocker (glibenclamide). The residual vasodilator effect of BRW observed in vessels pretreated with ChTx plus apamin is completely abolished by ChTx plus apamin plus L-NAME. Concentrations of atropine, pyrilamine, yohimbine, and HOE 140 that significantly reduced the vasodilator effect of acetylcholine, histamine, clonidine, and bradykinin, respectively did not change the vasodilator effect of BRW. Chronic oral administration of BRW induced a significant reduction in systolic, mean and diastolic arterial pressure in rats with L-NAME hypertension. The present results demonstrated that vasodilator effect of BRW is dependent on endothelium-derived hyperpolarizing factor (EDHF) in combination with nitric oxide (NO). The antihypertensive effect of red wine demonstrated in the present study may play a significant role on the cardioprotective action of chronic red wine consumption.
Assuntos
Consumo de Bebidas Alcoólicas/efeitos adversos , Bradicinina/análogos & derivados , Endotélio Vascular/fisiologia , Hipertensão/prevenção & controle , Vasodilatação/fisiologia , Acetilcolina/antagonistas & inibidores , Acetilcolina/farmacologia , Administração Oral , Animais , Apamina/farmacologia , Atropina/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Bradicinina/farmacologia , Brasil , Charibdotoxina/farmacologia , Clonidina/antagonistas & inibidores , Clonidina/farmacologia , Ácido Desoxicólico/farmacologia , Quimioterapia Combinada , Flavonoides/análise , Flavonoides/antagonistas & inibidores , Flavonoides/farmacologia , Glibureto/farmacologia , Guanilato Ciclase/antagonistas & inibidores , Hipertensão/induzido quimicamente , Indometacina/farmacologia , Masculino , Artérias Mesentéricas/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , NG-Nitroarginina Metil Éster/efeitos adversos , Óxido Nítrico Sintase/antagonistas & inibidores , Nitroglicerina/farmacologia , Norepinefrina/farmacologia , Oxidiazóis/química , Oxidiazóis/farmacologia , Perfusão , Fenóis/análise , Fenóis/antagonistas & inibidores , Fenóis/farmacologia , Polifenóis , Cloreto de Potássio/farmacologia , Pressão , Pirilamina/farmacologia , Quinazolinas/química , Quinazolinas/farmacologia , Quinoxalinas/farmacologia , Ratos , Ratos Wistar , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Vinho/efeitos adversos , Ioimbina/farmacologiaRESUMO
The effects of the essential oil of Ocimum gratissimum L. (Labiatae) (EOOG) on guinea pig ileum were studied. EOOG (0.1-1000 microg/ml) reversibly and concentration-dependently relaxed the basal tone of the ileum and reversed the tonic contractions induced by 60 mM KCl and 10 microM acetylcholine, with IC(50) values of 23.8+/-5.2, 18.6+/-4.0 and 70.0+/-4.6 microg/ml, respectively. Our results show that EOOG exerts relaxant effects on intestinal smooth muscle, consistent with the popular use of the plant to treat gastrointestinal disorders.