title: [The role of nitrogen oxide synthesis for relaxation of the internal anal sphincter].
abstract: The purpose of the present study was to examine the role of the L-arginine-nitric-oxide pathway in neurogenic relaxation of the internal anal sphincter. Muscle strips representing the internal anal sphincter were prepared from 17 adult opossums. The preparations were mounted in organ baths for recording of isometetric tension. N omega-nitro-L-arginine, an agent known to inhibit the L-arginine-nitric oxide pathway, concentration-dependently reduced relaxation induced by transmural field stimulation. At the highest concentration of N omega-nitro-L-arginine (10(-4) M), no relaxation was evoked at any frequency tested (0.5-40 Hz). The inhibitory response to exogenous VIP was unaffected by N omega-nitro-L-arginine pretreatment, indicating that VIP relaxation does not utilize the L-argining-nitric oxide pathway. It is concluded that the non-adrenergic, non-cholinergic innervation of the internal anal sphincter involves an inhibitory substance generated from the L-arginine--No pathway. Whether this substance is nitric oxide or a related nitroso compound remains to be settled.
authors.affiliation: Arhus Kommunehospital, kirurgisk afdeling L.
authors.forename: A
authors.initials: A
authors.lastname: Tøttrup
authors.forename: E B
authors.initials: EB
authors.lastname: Glavind
authors.forename: D
authors.initials: D
authors.lastname: Svane
mesh_terms: D001003:Anal Canal / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation / Q000378:metabolism; D009569:Nitric Oxide / Q000493:pharmacokinetics*; D019335:Nitroarginine; D009893:Opossums; D004561:Transcutaneous Electric Nerve Stimulation; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: D019335:Nitroarginine; D009569:Nitric Oxide; D014660:Vasoactive Intestinal Peptide; D001120:Arginine
vernacular_title: Betydningen af nitrogenoxidsyntese for relaksation af den interne anale sphincter.