Extraneuronal uptake inhibitor U-0521 decreases contractile responses in rat vas deferens.
1. The influence of catechol-O-methyltransferase inhibitor U-0521 on isotonic contraction of isolated rat vas deferens was examined to determine optimal concentration and nonspecific effects. 2. Maximum responses to (-)-epinephrine were increased at 0.4 microM and 1 microM concentrations of U-0521. Epinephrine responses were progressively decreased in the presence of higher concentrations (10 microM, 30 microM and 100 microM) of U-0521. 3. The response to the nonadrenergic agonist neurokinin A was similarly depressed in the presence of 100 microM U-0521. 4. U-0521 not only inhibits COMT, at concentrations above 1 microM it nonspecifically depresses contraction of the rat vas deferens by both adrenergic and nonadrenergic agonists.
Rice
P J
PJ
Department of Pharmacology, East Tennessee State University, Johnson City 37614, USA. RICE@ETSU-TN.EDU
Abraham
S T
ST
Huang
N Y
NY
Doman
R J
RJ
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D004837:Epinephrine / Q000494:pharmacology; D066298:In Vitro Techniques; D007551:Isotonic Contraction / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation*; D015288:Neurokinin A / Q000494:pharmacology; D014179:Neurotransmitter Uptake Inhibitors / Q000494:pharmacology*; D011427:Propiophenones / Q000494:pharmacology*; D051381:Rats; D014649:Vas Deferens / Q000187:drug effects / Q000294:innervation*
D000316:Adrenergic alpha-Agonists; D014179:Neurotransmitter Uptake Inhibitors; D011427:Propiophenones; C006104:U 0521; D015288:Neurokinin A; D002394:Catechol O-Methyltransferase; D004837:Epinephrine