Approaches to the mechanism of relaxing effect of vitamin K3 on smooth muscle.
Smooth muscle relaxing effect of vitamin K3 was tested by using isolated rat Vas deferens, normal and K+-depolarized rat duodenum. The contractions of the rat Vas deferens elicited by noradrenaline and phenylephrine were inhibited by vitamin K3, noncompetitively. Vitamin K3 inhibited the Ca2+-induced contractions of the K+-depolarized rat duodenum in a noncompetitive manner. The inhibitory effect of vitamin K3 on the K+-depolarized rat duodenum was evaluated by comparing it with that of verapamil, a well-known Ca2+-channel blocker and of trifluoperazine, a calmodulin inhibitor. Further, it was observed that vitamin K3 exerts a dose-dependent relaxing effect on the normal rat duodenum. The effect of vitamin K3 was compared with that of adrenaline, isoprenaline and papaverine. In addition, propranolol, a beta-adrenergic blocking agent, and nicotinic acid, an adenylate cyclase inhibitor, were used as tools in order to investigate the mechanism of the relaxing action of vitamin K3 on smooth muscle.
Department of Pharmacology, Faculty of Pharmacy, University of Ankara, Turkey.
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Oztürk
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004347:Drug Interactions; D004386:Duodenum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009467:Neuromuscular Depolarizing Agents; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D014649:Vas Deferens / Q000187:drug effects; D014812:Vitamin K / Q000494:pharmacology*
D009467:Neuromuscular Depolarizing Agents; D014812:Vitamin K; D010656:Phenylephrine; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine