摘要
:The dose-dependent hypotensive and bradycardic effects induced by an ichthyotoxic organophosphate compound isolated from the marine dinoflagellate Ptycholiscus brevis were studied. These effects were not antagonized by atropine, but potentiated by α-adrenoceptor blocker and hexamethonium. The toxin aboished the vasopressor effect elicited by phenyle phrine, indicating an α-adrenergic blocking activity. The cardiovascular depressor responses were antagonized by tetraethylammonium while blockade of cholinergic and histaminergic re ceptors or inhibition of prostaglandin synthesis failed to modify these effects. The results indi cate that the cardiovascular depressor effects of the toxin are probably mediated through α-a drenergic and ganglionic blockade accompanied by modulation of potassium channel activity
:The dose-dependent hypotensive and bradycardic effects induced by an ichthyotoxic organophosphate compound isolated from the marine dinoflagellate Ptycholiscus brevis were studied. These effects were not antagonized by atropine, but potentiated by α-adrenoceptor blocker and hexamethonium. The toxin aboished the vasopressor effect elicited by phenyle phrine, indicating an α-adrenergic blocking activity. The cardiovascular depressor responses were antagonized by tetraethylammonium while blockade of cholinergic and histaminergic re ceptors or inhibition of prostaglandin synthesis failed to modify these effects. The results indi cate that the cardiovascular depressor effects of the toxin are probably mediated through α-a drenergic and ganglionic blockade accompanied by modulation of potassium channel activity
