Anti - Muscarinic Effect Acetylcholine - Induced Isolated and Perfused Arteries of Alinidine on Vasodilation in Dog Coronary

NAKANE, T., FURUKAWA, Y. and CHIBA, S. Anti-Muscarinic Effect of Alinidine on Acetylcholine-Induced Vasodilation in Isolated and Perfused Dog Coronary Arteries. Tohoku J. Exp. Med., 1991, 165 (2),105-113 The effect of alinidine, a bradycardic agent, on the vasodilator responses to acetylcholine was examined in isolated and perfused dog coronary arteries. Single injections of acetylcholine (10-12-10-6 mol) and carbachol (10-10-10-6 mol) produced dosedependent vasodilations. The endothelial removal by a bolus injection of saponin (1 mg) inhibited those vasodilations. Alinidine (10-6 M) shifted the dose-response curves of acetylcholine and carbachol to the right, but it did not affect those for isosorbide dinitrate, isoproterenol and adenosine. The rank order of potency of muscarinic antagonists for inhibiting the a~,etylcholine-induced vasodilation was 4-DAMP > atropine > AF-DX 116 > pirenzepine > alinidine. Alinidine was approximately 100 times less potent than atropine. Single injection of alinidine (10-8-10-6 mol) dilated the dog coronary artery in a dose-related manner. The vasodilation was not affected by the pretreatment with phentolamine (10-6 M), pindolol (10-6 M), atropine (10-6 M), chlorpheniramine (10-6 M), cimetidine (10-6 M) or methysergide (10-6 M). These results suggest that alinidine has a weak anti-muscarinic effect on the endothelium-dependent vasodilation of the dog coronary artery. alinidine ; acetylcholine ; muscarinic receptor ; dog coronary artery ; endothelium