The mode of action of ifenprodil tartrate in isolated canine cerebral and femoral arteries.
Tension of isolated rings of cerebral and femoral arteries was measured isometrically and Ca2+ movement in these arteries was measured by 45Ca flux to study the mode of action of ifenprodil tartrate (IFT). IFT (10(-7)-10(-4) M) induced relaxation in basilar and femoral arteries contracted by K+ (50 mM). During normoxia (O2 aeration) it induced contraction in arteries contracted by prostaglandin (PG)F2 alpha (10(-5) M), but induced relaxation during hypoxia (N2 aeration). In K+-induced contraction the relaxed tension induced by IFT was reversed by addition of Ca2+ in a dose-dependent manner. The IFT induced relaxation of femoral arteries contracted by K+ was attenuated in Ca2+-free solution containing 0.1 mM EGTA, and the effect of IFT on basilar and femoral arteries contracted by PGF2 alpha was reversed. IFT inhibited K+-induced Ca2+ uptake in cerebral and femoral arteries. IFT enhanced PGF2 alpha-induced Ca2+ uptake in cerebral arteries under normoxia, but inhibited it under hypoxia. The results suggest that the action of IFT may be due to alteration of Ca2+ utilization by vascular cells through blockade of potential-sensitive channels, and this action may reflect regional differences between arteries.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000502:physiology; D002536:Cerebral Arteries / Q000187:drug effects; D015237:Dinoprost; D004285:Dogs; D005260:Female; D005263:Femoral Artery / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D010880:Piperidines; D011460:Prostaglandins F; D015237:Dinoprost; C010739:ifenprodil; D011188:Potassium; D010100:Oxygen; D002118:Calcium