Differences in the effects of acetylcholine on the vas deferens from normal and castrated rats. A participation of adrenergic mechanisms.
The epididymal portion of the rat vas deferens from normal and castrated rats exhibited clear differences regarding both the threshold and the maximal response to acetylcholine. Alpha adrenoceptor antagonists, hexamethonium and 6-hydroxydopamine diminished the effectiveness of low acetylcholine concentrations on normal and castrated preparations of the epididymal portion of isolated rat vas deferens, but did not influence the maximal response. On the other hand, desipramine enhanced the action of low concentrations of acetylcholine, both in threshold and maximal response; but failed to alter the reactivity to high concentrations of acetylcholine. The results obtained suggest that low doses of acetylcholine may affect the contractile function of the isolated epididymal portion of rat vas deferens by producing a release of norepinephrine from presynaptic sites and acts in a similar fashion on preparations from both normal and castrated animals.
D000109:Acetylcholine / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D002369:Castration; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects*; D013737:Testis / Q000502:physiology*; D014649:Vas Deferens / Q000187:drug effects*
D000317:Adrenergic alpha-Antagonists; D011941:Receptors, Adrenergic; D000109:Acetylcholine; D009638:Norepinephrine