title: Antagonist of nitric oxide synthesis inhibits nerve-mediated relaxation of isolated strips of rumen and reticulum.
abstract: The present study investigated the possibility that nitric oxide is a nonadrenergic, noncholinergic neurotransmitter of nerves that are intrinsic to the forestomach. Tunica muscularis, myenteric plexus preparations of bovine reticulum and rumen were maintained in vitro in a physiological solution of buffer that contained scopolamine. Trains of electric field stimulation transiently reduced (relaxed) the tone induced by BaCl2. NG-Nitro-L-arginine methyl ester, a nitric oxide synthase competitive antagonist, inhibited relaxation of the rumen and reticulum preparations that had been induced by the electrical field. The actions of NG-nitro-L-arginine methyl ester were partially reversed by L-arginine. These data suggest that nitric oxide, or a related substance, is an inhibitory neurotransmitter of nerves that are intrinsic to tunica muscularis, myenteric plexus preparations of the bovine forestomach.
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Schneider
authors.forename: S C
authors.initials: SC
authors.lastname: Eades
mesh_terms: D000818:Animals; D017609:Barium Compounds / Q000494:pharmacology; D002417:Cattle / Q000502:physiology*; D002712:Chlorides / Q000494:pharmacology; D004558:Electric Stimulation; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D012159:Reticulum / Q000294:innervation* / Q000502:physiology; D012417:Rumen / Q000294:innervation* / Q000502:physiology; D012601:Scopolamine / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D017609:Barium Compounds; D002712:Chlorides; D018727:Muscarinic Antagonists; C024986:barium chloride; D013779:Tetrodotoxin; D012601:Scopolamine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester