5-hydroxytryptamine: source of activator calcium in human basilar arteries.
We performed experiments in human cerebral arteries to determine the source of activator calcium during contractions induced by 5-hydroxytryptamine. Rings of human basilar artery obtained at autopsy were mounted for isometric tension recording in organ baths filled with a physiological salt solution. Contractile responses to 5-hydroxytryptamine were virtually abolished in Ca++-free solution, and inhibited significantly by nimodipine. In both cases, the depression of the response to 5-hydroxytryptamine was comparable to that seen when KCl was used to contract the vessels. These experiments demonstrate that 5-hydroxytryptamine mediates contraction of the smooth muscle in human basilar artery by increasing membrane permeability to extracellular calcium.
D000328:Adult; D000368:Aged; D001488:Basilar Artery / Q000187:drug effects*; D002118:Calcium / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002199:Capillary Permeability / Q000187:drug effects; D002536:Cerebral Arteries / Q000187:drug effects; D006801:Humans; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009539:Nicotinic Acids / Q000494:pharmacology; D009553:Nimodipine; D012701:Serotonin / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D009539:Nicotinic Acids; D012701:Serotonin; D009553:Nimodipine; D002118:Calcium