Abstract
The inhibitory effect of dichlorovos (an organophosphate pesticide) on Ca
2+-dependent contractions has been studied in isolated helical strips of rat tail arteries. Isometric contractions were evaluated under standard organ bath conditions. Dichlorovos caused concentration-dependent relaxation of 10
−7
M NE-induced contractions as well as inhibition of both phasic and tonic components of NE contractions. Extracellular calcium-dependent contractions in K
+-depolarized medium as well as NE-induced contractions due to mobilization of membranebound calcium pool and intracellular calcium-dependent caffeine contractions were significantly attenuated by dichlorovos. The results strongly support our previous observation that dichlorovos interferes with calcium metabolism in the rat tail artery.