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.
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, UK.
A H
AH
Clark
C J
CJ
Garland
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