EXTRANEURONAL UPTAKE INHIBITOR U-0521 DECREASES CONTRACTILE RESPONSESIN RAT VAS-DEFERENS

1. The influence of catechol-O-methyltransferase inhibitor U-0521 on i sotonic contraction of isolated rat vas deferens was examined to deter mine optimal concentration and nonspecific effects. 2. Maximum respons es to (-)-epinephrine were increased at 0.4 mu M and 1 mu M concentrat ions of U-0521. Epinephrine responses were progressively decreased in the presence of higher concentrations (10 mu M, 30 mu M and 100 mu M) of U-0521. 3. The response to the nonadrenergic agonist neurokinin A w as similarly depressed in the presence of 100 mu M U-0521. 4. U-0521 n ot only inhibits COMT, at concentrations above 1 mu M it nonspecifical ly depresses contraction of the rat vas deferens by both adrenergic an d nonadrenergic agonists. (C) 1997 Elsevier Science Inc.