Evidence for a role of nitric oxide in the neurotransmitter system mediating relaxation of the rat anococcygeus muscle.
1. The nitric oxide (NO) synthesis inhibitor NG-monomethyl-L-arginine (L-NMMA), but not D-NMMA, inhibited the NANC-mediated relaxations of the rat anococcygeus muscle, but did not affect the relaxation produced by sodium nitroprusside. 2. The inhibitory effect of L-NMMA was reversed by L-arginine but not by D-arginine, and prior exposure to L-arginine blocked the effect of L-NMMA. 3. The noradrenergically mediated contractions of the anococcygeus elicited by field stimulation were slightly enhanced by L-NMMA, but the response to noradrenaline was not affected. 4. The results suggest that NANC transmission in the rat anococcygeus muscle involves the generation of NO from arginine.
Li
C G
CG
Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia.
Rand
M J
MJ
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009132:Muscles / Q000187:drug effects*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013237:Stereoisomerism; D009435:Synaptic Transmission / Q000187:drug effects*; D019323:omega-N-Methylarginine
D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine