Evidence of P2Y-purinoceptor mediated bladder neck smooth muscle post-contractile relaxation in the male mini-pig.
The functional role of non-adrenergic non-cholinergic (NANC) nerves in the autonomic control of the male mini-pig bladder neck was investigated in the present study. Electrical stimulation of muscle strips from male mini-pig bladder neck showed biphasic response with initial phasic contraction followed by post-contractile relaxation. Electrical stimulation in the presence of four autonomic blockers (atropine 10(-6) M, propanolol 10(-6) M, phentolamine 10(-6) M) showed suppression of 68 +/- 15% of the contractile response (P < 0.05, n = 8) but no significant change in the relaxation response. Alpha-chymotrypsin 2 U/ml, L-NG-monomethyl-L-arginine acetate (a nitric oxide synthetase inhibitor) 10(-4) M, 8-phenylthlophylline (a P1-purinoceptor antagonist) 10(-6) M, and pyridoxal-phosphate-6-azophenyl-2', 4'-disulphoric acid tetrasodium salt (a P2Y-purinoceptor antagonist) 3 x 10(-5) M did not alter the NANC response significantly. On the other hand, reactive blue-2 (a P2Y-purinoceptor antagonist) 3 x 10(-5) significantly reduced the relaxation by 79 +/- 9%. The result suggested that the P2Y-purinoceptor is involved in the electrically induced NANC post-contractile relaxation of the mini-pig bladder neck smooth muscle.
Tong
Y C
YC
Department of Urology, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan, ROC.
Hung
Y C
YC
Cheng
J T
JT
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004558:Electric Stimulation; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D011983:Receptors, Purinergic / Q000187:drug effects*; D013552:Swine; D001743:Urinary Bladder / Q000187:drug effects*
D011983:Receptors, Purinergic; D001285:Atropine