5-hydroxytryptamine-stimulated accumulation of 1,2-diacylglycerol in the rabbit basilar artery: a role for protein kinase C in smooth muscle contraction.
1. 5-Hydroxytryptamine (5-HT) produced a concentration-dependent increase in the membrane concentration of 1,2-diacylglycerol (DG) in the rabbit isolated basilar artery, but did not stimulate the hydrolysis of membrane phosphoinositide. 2. The 5-HT-induced accumulation of DG could be blocked with the putative phospholipase C inhibitor 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (NCDC; 70 microM), but not with the protein kinase C inhibitor, 1-(5-isoquinolinesulphonyl)-2-methyl piperazine (H7; 50 microM). 3. Direct stimulation of protein kinase C with phorbol 12,13-dibutyrate (PDBu) produced sustained smooth muscle contraction which was fairly rapid in onset and could be reversed by H7 but not by NCDC. The inactive phorbol, 4 alpha phorbol 12,13-dideceonate, did not produce contraction in the basilar artery. 4. 5-HT-induced contractions (1 nM-100 microM) were blocked or greatly reduced in the presence of the protein kinase inhibitor H7 or polymyxin B, and with the phospholipase C inhibitor, NCDC. The concentrations of these inhibitors which abolished contraction to 5-HT, did not alter smooth muscle contraction produced in response to 30 mM K(+)-physiological salt solution (PSS). 5. These data suggest that DG production and the subsequent activation of PKC forms an important component of the cerebrovascular contractile response to 5-HT. As the DG does not appear to arise from membrane phosphatidylinositol, it appears that 5-HT can stimulate the production of this second messenger in cerebral arteries by a mechanism which is different from peripheral arteries.
Clark
A H
AH
Department of Physiology and Pharmacology, University of Southampton.
Garland
C J
CJ
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D004075:Diglycerides / Q000096:biosynthesis*; D005260:Female; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology*
C011439:1,2-diacylglycerol; D004075:Diglycerides; D007295:Inositol Phosphates; D007546:Isoquinolines; D010879:Piperazines; D012701:Serotonin; D015240:Phorbol 12,13-Dibutyrate; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C