Evidence for protein kinase C modulation of the ciliary muscle response to carbachol and desensitization.
The role of protein kinase C (PKC) in the desensitization of muscarinic receptor-mediated responses in bovine ciliary muscle was examined. Exposure of the bovine ciliary muscle to phorbol esters, used to activate PKC, resulted in antagonism of muscarinic receptor-mediated contraction. On the other hand, staurosporine, a known PKC inhibitor, caused a significant potentiation of the contractile effect induced by carbachol. Staurosporine reduced the desensitization induced by repeated additions of carbachol and completely suppressed that induced by phorbol esters. The results also indicate that desensitization mediated by phorbol esters as well as that mediated by muscarinic receptor agonists is heterologous.
Lograno
M D
MD
Pharmacobiological Department, University of Bari, Italy.
Daniele
E
E
Trabucchi
M
M
Govoni
S
S
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D002417:Cattle; D002924:Ciliary Body / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D004075:Diglycerides / Q000378:metabolism; D015237:Dinoprost / Q000494:pharmacology; D004789:Enzyme Activation; D018727:Muscarinic Antagonists; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D019311:Staurosporine; D013373:Substance P / Q000494:pharmacology
D000470:Alkaloids; D004075:Diglycerides; D018727:Muscarinic Antagonists; D010703:Phorbol Esters; D013373:Substance P; D015240:Phorbol 12,13-Dibutyrate; D002217:Carbachol; D015237:Dinoprost; D011493:Protein Kinase C; D019311:Staurosporine