title: The relaxing response of the isolated rat duodenum to nicotine.
abstract: 1. The relaxing responses of the atropine-treated isolated rat duodenum to 12 microM nicotine (N) and transmural electrical stimulation (S) have been compared. 2. The effects of both N and S were unaffected by 3-30 microM guanethidine or previous reserpinization (1 mg/kg, i.p. during 5 days). 3. The effects of N and S were completely blocked by 0.5-2.0 mM procaine, 0.1 mM butacaine or 0.3-1.2 microM tetrodotoxin. 4. The relaxing response to N but not that to S was blocked by 0.3 mM hexamethonium or 3 microM mecamylamine and absent in the nicotine-desensitized preparation. 5. The effects of both N and S were unaffected in the adenosine-5'-triphosphate (ATP)-desensitized preparation. 6. It is suggested that the nonadrenergic and noncholinergic (NANC) relaxation of the rat duodenum in response to N and S is also nonpurinergic.
authors.affiliation: Departmento de Farmacologia, Faculdade de Medicina de Ribeiráo Preto-U.S.P., Brazil.
authors.forename: C R
authors.initials: CR
authors.lastname: Guimaraes
authors.forename: L A
authors.initials: LA
authors.lastname: Rodrigues
authors.forename: O
authors.initials: O
authors.lastname: Vettore
authors.forename: A
authors.initials: A
authors.lastname: Antonio
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000187:drug effects; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D004386:Duodenum / Q000187:drug effects; D004558:Electric Stimulation; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D011343:Procaine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012110:Reserpine / Q000494:pharmacology
chemical_list: D011343:Procaine; D004246:Dimethylphenylpiperazinium Iodide; D009538:Nicotine; D001285:Atropine; D012110:Reserpine; D000255:Adenosine Triphosphate; D006145:Guanethidine