Tonic and rhythmic contractions induced by dopamine and related amines in rat vasa deferentia are pharmacologically separable.
1. Exogenous dopamine (DA), octopamine (OA), noradrenaline (NA), and the alpha 1-agonist methoxamine (MX), all induce tonic and rhythmic contractions in the rat vas deferens. 2. Tonic and rhythmic contractions can be separated by use of different concentrations of alpha 1-adrenoceptor antagonists, verapamil, pyrogallol (a COMT-inhibitor) and lowering bath temperature (greater than 20 degrees C). 3. The two types of contraction could not be distinguished by beta-adrenoceptor antagonists, cocaine (uptake 1 blocker) or metanephrine (uptake 2 blocker). 4. It is suggested that the tonic and rhythmic contractions induced by amines are mediated by different alpha-adrenoceptors.
Lafi
M A
MA
School of Biological Sciences, Portsmouth Polytechnic, Hants, UK.
Leake
L D
LD
D000588:Amines / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000502:physiology; D002217:Carbachol / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009655:Octopamine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011748:Pyrogallol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013696:Temperature; D014439:Tyramine / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects
D000588:Amines; D011748:Pyrogallol; D009655:Octopamine; D002217:Carbachol; D008729:Methoxamine; D003042:Cocaine; D002118:Calcium; D004298:Dopamine; D014439:Tyramine; D011224:Prazosin