TY - JOUR T1 - EXCITATION OF THE PARASYMPATHETIC GANGLIA OF THE CANINE URINARY BLADDER THROUGH A MUSCARINIC MECHANISM JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 93 LP - 100 VL - 176 IS - 1 AU - NORIO TAIRA AU - SATOSHI MATSUMURA AU - KOROKU HASHIMOTO Y1 - 1971/01/01 UR - http://jpet.aspetjournals.org/content/176/1/93.abstract N2 - For close-arterial injection the urinary bladder was autoperfused with arterial blood through the caudal vesical arteries in dogs anesthetized with pentobarbital. Intra-arterial injection of 4-(m-chlorophenylcarbamoyoxy)-2-butynyltrimethylammonium chloride (McN A-343), known as a muscarinic sympathetic ganglionic stimulant, caused a contraction of the bladder. The potency of McN A-343 in producing a contraction of the bladder was roughly 1/10 that of 1, 1-dimethyl-4-phenylpiperazinium iodide. In most experiments the response to McN A-343 was abolished by tetrodotoxin, and in all observations it was potentiated by physostigmine but not affected by guanethidine. This indicates that the response to McN A-343 was caused by excitation of the intramural parasympathetic ganglia. The fact that the response to McN A-343 was resistant to blockade by hexamethonium or tetraethylammonium and susceptible instead to blockade by a small dose of atropine indicates further that excitation of the parasympathetic ganglia of the bladder by McN A-343 was mediated through muscarinic rather than nicotinic receptors. © 1971, by The Williams & Wilkins Company ER -