title: Inhibitory effect of dichlorvos on arterial smooth muscle contraction.
abstract: The effect of the organophosphate pesticide, dichlorvos, on the contractile responses of isolated rat tail arteries has been studied. Dichlorvos (10(-8)-10(-4) M) had no effect on baseline tension, but relaxed 10(-7) M norepinephrine (NE), 10(-7) M 5-HT or 100 mM KCl contractions dose-dependently. Dichlorvos also inhibited CaCl2 dose-response curves in K+-depolarized strips, as well as depressing both phasic and tonic components of NE-induced contractions. The results suggest a direct relaxant effect of dichlorvos on arterial smooth muscle by a mechanism probably related to interference with Ca2+ supply.
mesh_terms: D000818:Animals; D001158:Arteries / Q000187:drug effects; D002122:Calcium Chloride / Q000037:antagonists & inhibitors; D004006:Dichlorvos / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000037:antagonists & inhibitors; D051381:Rats; D012702:Serotonin Antagonists; D013623:Tail / Q000098:blood supply; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D012702:Serotonin Antagonists; D004006:Dichlorvos; D002122:Calcium Chloride; D009638:Norepinephrine