Ca2+ channel antagonists and inhibition of protein kinase C each block contraction but not depolarization to 5-hydroxytryptamine in the rabbit basilar artery.
The Ca2+ channel antagonists nifedipine and verapamil each significantly inhibited (50-100%) the smooth muscle contraction induced in response to either 5-hydroxytryptamine (1 microM, 5-HT) or 20 mM K+ (K(+)-physiological salt solution) in the basilar artery. Simultaneous measurements of smooth muscle membrane potential showed that changes in potential were not modified at this time. A similar inhibitory action against the smooth muscle contraction but not the depolarization to 5-HT was obtained with the putative protein kinase C and phospholipase C inhibitors, 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (10 microM, H7) and 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (70 microM, NCDC). These data indicate that 5-HT-induced Ca2+ influx through voltage sensitive channels is important for smooth muscle contraction but not depolarization in the rabbit basilar artery.
Clark
A H
AH
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, UK.
Garland
C J
CJ
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D001488:Basilar Artery / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002219:Carbamates / Q000494:pharmacology; D005260:Female; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009543:Nifedipine / Q000494:pharmacology; D048448:Phenylcarbamates; D010879:Piperazines / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D002219:Carbamates; D007546:Isoquinolines; D048448:Phenylcarbamates; D010879:Piperazines; C025508:2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate; D012701:Serotonin; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D014700:Verapamil; D011493:Protein Kinase C; D010738:Type C Phospholipases; D009543:Nifedipine; D011188:Potassium