title: Inhibitory effects of quercetin and staurosporine on phasic contractions in rat vascular smooth muscle.
abstract: The aim of this work was to analyze the effects of quercetin and staurosporine on the phasic contractile responses in rat aorta induced by noradrenaline, 5-hydroxytryptamine (5-HT, serotonin) and caffeine in Ca(2+)-free media. Both quercetin and staurosporine inhibited the contractions induced by 10(-5) M noradrenaline, 10(-5) M 5-HT and 20 mM caffeine in Ca(2+)-free solution. Phorbol 12-myristate 13-acetate (5 x 10(-8) M) enhanced this transient contraction elicited by noradrenaline, an effect that was abolished by quercetin (5 x 10(-5) M). The relaxant effects of quercetin on 80 mM KCl induced contractions were similar in normal and low Na+ solution, e.g. when Ca2+ efflux through the Na+/Ca2+ exchanger was inhibited. Furthermore, quercetin or staurosporine had no effect on 45Ca2+ efflux under resting conditions or when stimulated by 10(-5) M noradrenaline. These results suggested that the inhibitory effects of quercetin and staurosporine on phasic contractile responses induced by receptor agonists in Ca(2+)-free media do not seem to be related to changes in cellular Ca2+ regulation but to an inhibitory effect on the regulation of contractile proteins, an effect probably related to the decreased sensitivity of contractile elements to Ca2+ that apparently resulted from the inhibitory effects of quercetin and staurosporine on protein kinases.
authors: Department of Pharmacology, School of Pharmacy, University of Granada, Spain.
authors: J
authors: J
authors: Duarte
authors: F
authors: F
authors: Pérez-Vizcaíno
authors: A
authors: A
authors: Zarzuelo
authors: J
authors: J
authors: Jiménez
authors: J
authors: J
authors: Tamargo
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D011794:Quercetin / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D012701:Serotonin; D002110:Caffeine; D011189:Potassium Chloride; D011794:Quercetin; D012964:Sodium; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; D009638:Norepinephrine