title: Interference of pentobarbitone with the contraction of vascular smooth muscle in goat middle cerebral artery.
abstract: Pentobarbitone (10(-5) to 10(-3) M) decreased the basal tone of vascular smooth muscle of goat middle cerebral artery in a dose-dependent manner as well as relaxing established contractions induced by noradrenaline (NA) (10(-5) M), 5-hydroxytryptamine (5-HT) (10(-5) M) and KCl(120 mM). Preincubations with pentobarbitone reduced the contractions evoked by these three agents in a dose-dependent way. It also decreased Ca2+ -induced contractile responses in K+ -depolarized arteries and 5-HT-Ca2+ and NA-Ca2+ contractions dose-dependently. Contractions induced by K+ were more sensitive to the depressant actions of the drug than those produced by NA and 5-HT. The small contractions evoked by K+ and 5-HT in Ca2+ -free medium were also reduced in its presence. The antagonism Ca2+ -pentobarbitone was insurmountable. These results suggest that the drug interferes with Ca2+ entry and Ca2+ release from cells stores, and therefore with the smooth muscle contractions.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002536:Cerebral Arteries / Q000187:drug effects; D005260:Female; D006041:Goats; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology
chemical_list: D012701:Serotonin; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine; D010634:Phenobarbital