title: Participation of muscarinic acetylcholine receptors in nitric oxide pathway in cat duodenum.
abstract: The effect of activation of muscarinic acetylcholine subtype M1 receptors on the electrical field stimulation (EFS)-induced contractions in cat duodenal muscle strips was investigated. EFS elicited two types of responses: a) on-contraction; and b) off-contraction. The EFS-evoked responses were tetrodotoxin- and atropine-sensitive. In all strips the muscarinic acetylcholine subtype M1 agonist (4-Hydroxy-2-butynyl)-1-trimethylammonium-m-chlorocarbanilate chloride (McN-A-343) increased the tone and the amplitude of the spontaneous contractions. On this background EFS produced an inhibition of the phasic contractions at switching on the stimulation, followed by off-contractions. The EFS-induced inhibition was removed by N omega-nitro-L-arginine and was partly overcome by L-arginine. The results suggest the participation of muscarinic acetylcholine subtipe M1 receptors in the mediation of nitrergic inhibitory responses in cat duodenum.
authors.affiliation: Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors.forename: L I
authors.initials: LI
authors.lastname: Shikova
authors.forename: N I
authors.initials: NI
authors.lastname: Kortezova
mesh_terms: D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D002415:Cats; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism*; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D019335:Nitroarginine / Q000494:pharmacology; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D018721:Muscarinic Agonists; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic; D019335:Nitroarginine; D009569:Nitric Oxide; D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride; D001120:Arginine; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III