Cerebral arterial spasm: part 9. In vitro effects of nifedipine on serotonin-, phenylephrine-, and potassium-induced contractions of canine basilar and femoral arteries.
We performed in vitro experiments with a small volume chamber to determine the inhibitory effect of nifedipine on serotonin-, phenylephrine-, and potassium-induced contractions of canine basilar and  femoral arteries. Nifedipine, an inhibitor of the influx of extracellular calcium into smooth muscle cells, was found to be a sensitive inhibitor of contractions of the basilar artery induced by all three agents. In contrast, nifedipine did not significantly inhibit the serotonin- and phenylephrine-induced contractions of the femoral artery but did inhibit potassium-induced contractions of the femoral artery. Calcium-induced contractions of the  basilar artery were also inhibited by nifedipine. These experiments demonstrate a relatively selective effect of nifedipine on the basilar artery, and a mechanism to explain this selective effect is postulated.
D000818:Animals; D001488:Basilar Artery / Q000187:drug effects*; D002118:Calcium / Q000502:physiology; D002539:Cerebral Arterial Diseases / Q000503:physiopathology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004336:Drug Antagonism; D005260:Female; D005263:Femoral Artery / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D012701:Serotonin / Q000494:pharmacology*; D013035:Spasm / Q000139:chemically induced / Q000503:physiopathology*; D014661:Vasoconstriction / Q000187:drug effects
D011725:Pyridines; D010656:Phenylephrine; D012701:Serotonin; D009543:Nifedipine; D011188:Potassium; D002118:Calcium