title: Effects of flunarizine on electrical and mechanical responses of smooth muscle cells in basilar and ear arteries of the rabbit.
abstract: The effects of flunarizine on electrical and mechanical responses of smooth muscle tissues of the rabbit basilar and ear arteries to transmural stimulation, high-potassium solution (high-K), 5-hydroxytryptamine and noradrenaline were studied. In the basilar artery, 10(-6) M flunarizine (69 min application) blocked spike potentials generated by outward current stimuli or transmural stimulation without change in the resting-membrane potential or membrane resistance. The spike potentials generated in the ear artery were attenuated by a long exposure (up to 2 h) to a high concentration of flunarizine (10(-6) M). Membrane depolarizations produced by high-K, noradrenaline or 5-hydroxytryptamine were not blocked by flunarizine. Flunarizine inhibited smooth muscle contractions produced by transmural stimuli, high-K, noradrenaline or 5-hydroxytryptamine in both arteries, however the inhibition developed slowly, and the ear artery required a longer period of incubation with flunarizine than the basilar artery. The inhibitory effects of flunarizine on basilar artery were more marked against transmural stimulation or high-K induced contractions than against agonist-induced contractions.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001488:Basilar Artery / Q000187:drug effects; D004423:Ear / Q000098:blood supply; D004558:Electric Stimulation; D005444:Flunarizine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011188:Potassium / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology
chemical_list: D012701:Serotonin; D005444:Flunarizine; D011188:Potassium