Effect of Baclofen on the Cholinergic Nerve Stimulation in Isolated Rat Detrusor / 영남의대학술지

ABSTRACT

This study aimed to investigate the mechanism of action of baclofen on the detrusor muscle isolated from rat. Rats (Sprague-Dawley) were sacrificed by decapitation and exsanguination. Horizontal muscle strips of 2 mm x 15mm were prepared for isometric myography in isolated muscle chamber bubbled with 95% / 5%-OZ / CO2 at 371C, and the pH was maintained at 7.4 Detrusor strips. contracted responding to the.. electrical field stimulation (EFS) by 2 Hz, 2U msec, monophasic square wave of 60 VDC. The initial peak of EFS-Induced contraction was tended to be suppresed by a,p-methylene-adenosine 5'-triphosphate (mATP), a partial agonist of purinergic receptor, and baclofen, a GABAB receptor agonist (statistically nonsignificant). The late sustained contraction by EFS was suppressed significantly (p < 0.05) by additions of atropione, a cholinergic muscarinic receptor antagonist and baclofen. The adenosine 5'-triphosphate-induced contraction was completely abolished by mA TP but not by baclofen. In the presence of atropine, the subsequent addition of acetylcholine could not contract the muscle strips but the addition of acetylcholine in the presence of baclofen evoked a contraction to a remarkable extent.