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BmK I, an alpha-like scorpion neurotoxin, specifically modulates isolated rat cardiac mechanical and electrical activity / 生理学报
Acta Physiologica Sinica ; (6): 530-534, 2003.
Artigo em Inglês | WPRIM | ID: wpr-290932
ABSTRACT
In this study, cardiotonic and cardiotoxic effects of Buthus martensi Karsch (BmK) I, a modulator of voltage-gated sodium channels, were investigated on the isolated rat hearts. The results showed that BmK I evoked complex effects characterized by a change in both cardiac mechanical and electrical activity. Langendorff perfusion showed that (1) maximal left ventricular developed pressure (LVDP(max)) and dp/dt(max) were markedly increased by BmK I (0.5-10 micromol/L) in a dose-dependent manner (n=6, P<0.05), positive chronotropic effects were also induced by BmK I (n=6, P<0.05); (2) negative inotropic action and bradycardia could be elicited at a larger dose of BmK I (20 micromol/L); (3) the coronary flow varied inversely with the positive inotropic effects, coronary flow reduced during positive inotropic effects from 14.5 to 8.6 ml/min after administration of 500 nmol/L BmK I (n=6, P<0.05). In addition, tachycardia and complex cardiac arrhythmias were induced by BmK I (0.5-10 micromol/L). The modulating of BmK I on the heart mechanical, electrical activity could be partially recovered after washing. As propranolol was applied to block the release of catecholamines before administration of BmK I, suggesting that the changes in cardiac mechanical and electrical activity induced by BmK I might not due to catecholamine release from the nerve terminal and subsequent stimulation of the beta-adrenoceptor but attributable to the modulation of BmK I on cardiac voltage-gated sodium channels.
Assuntos
Texto completo: DisponíveL Índice: WPRIM (Pacífico Ocidental) Assunto principal: Farmacologia / Venenos de Escorpião / Técnicas In Vitro / Potenciais de Ação / Canais de Sódio / Ratos Sprague-Dawley / Técnicas de Patch-Clamp / Proteínas de Insetos / Bloqueadores dos Canais de Sódio / Eletrofisiologia Limite: Animais Idioma: Inglês Revista: Acta Physiologica Sinica Ano de publicação: 2003 Tipo de documento: Artigo

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Texto completo: DisponíveL Índice: WPRIM (Pacífico Ocidental) Assunto principal: Farmacologia / Venenos de Escorpião / Técnicas In Vitro / Potenciais de Ação / Canais de Sódio / Ratos Sprague-Dawley / Técnicas de Patch-Clamp / Proteínas de Insetos / Bloqueadores dos Canais de Sódio / Eletrofisiologia Limite: Animais Idioma: Inglês Revista: Acta Physiologica Sinica Ano de publicação: 2003 Tipo de documento: Artigo