A phorbol ester inhibits the release of endothelium-derived relaxing factor.
The effect of the phorbol ester phorbol-12,13-dibutyrate (PDB), an activator of protein kinase C, on endothelium-dependent relaxation was studied in noradrenaline-constricted isolated aortic ring preparations of the rabbit. Endothelium-dependent relaxation induced by acetylcholine or substance P was inhibited by PDB (greater than or equal to 10(-7) M). Endothelium-dependent relaxation induced by the calcium ionophore A23187 (7.5 X 10(-8) and 10(-7) M) was unaffected by PDB (to 10(-6) M). The mechanical responses to acetylcholine or sodium nitroprusside in endothelium-denuded rings were not altered by PDB (to 10(-6) M). The results suggest a role for protein kinase C in receptor-mediated EDRF release mechanisms.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002273:Carcinogens / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009569:Nitric Oxide; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology*; D011817:Rabbits; D014665:Vasodilator Agents / Q000378:metabolism*
D002273:Carcinogens; D010703:Phorbol Esters; D014665:Vasodilator Agents; D009599:Nitroprusside; C008876:phorbol-12,13-didecanoate; D009569:Nitric Oxide; D015240:Phorbol 12,13-Dibutyrate; D000001:Calcimycin; D009638:Norepinephrine