POST-NATAL CHANGE IN THE EFFECT OF DENERVATION ON THE RAT VAS DEFERENS

¹ Departments of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Tokyo 113
² Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Nagoya City University, Tanabe-Dohri 3-1, Mizuho-Ku, Nagoya, 467 Japan

The vas deferens of 14-54 d old rats was denervated, isolated after 7 d, divided into prostatic and epididymal halves, and denervation supersensitivity to noradrenaline, acetylcholine, methacholine and tetramethylammonium (TMA) was examined. The supersensitivity to any of these agonists did not appear in rats younger than 21 d of age. Thereafter a leftward shift of the dose-response curve and an increase in the maximum contraction to noradrenaline were observed. The maximum contraction became progressively greater with development in the prostatic half but was approximately constant in the epididymal half. Supersensitivity to methacholine distinctly developed with age in the epididymal half. Only a subsensitivity to TMA was observed, suggesting that TMA acts on the nerve. The effect of denervation on the response to acetylcholine in the epididymal half resembled that to methacholine, and in the prostatic half resembled that to TMA. The developmental change in the effect of denervation on noradrenaline was discussed in relation to the full contractile ability of the vas halves, and that to cholinergic drugs was discussed in relation to nicotinic and muscarinic receptor population.