title: Influence of nitric oxide donors and of the alpha(2)-agonist UK-14,304 on acetylcholine release in the pig gastric fundus.
abstract: This study in circular muscle strips of the pig gastric fundus aimed to measure the release of acetylcholine directly and to investigate whether NO and alpha(2)-adrenoceptor agonists can modulate acetylcholine release from cholinergic neurones. After incubation of the tissues with [(3)H]-choline, basal and electrically induced release of tritium and [(3)H]-acetylcholine were analyzed in a medium containing physostigmine (10(-5) M) as well as atropine (10(-6) M). The NO synthase inhibitor L-N(G)-nitroarginine methyl ester (3x10(-4) M), and the NO donors sodium nitroprusside (10(-5) M) and 3-morpholino-sydnonimine (10(-5) M) did not influence the basal release nor the electrically evoked release, indicating that NO does not modify [(3)H]-acetylcholine release. The alpha(2)-adrenoceptor agonist UK-14,304 (10(-5) M) significantly inhibited the electrically evoked release of [(3)H]-acetylcholine, and this effect was prevented by the alpha(2)-adrenoceptor antagonist rauwolscine (2x10(-6) M), suggesting that presynaptic alpha(2)-adrenoceptors are present on cholinergic neurones of the pig gastric fundus.
authors: Heymans Institute of Pharmacology, Ghent University Faculty of Medicine, De Pintelaan 185, B-9000 Ghent, Belgium.
authors: P G
authors: PG
authors: Leclere
authors: R A
authors: RA
authors: Lefebvre
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D000068438:Brimonidine Tartrate; D002851:Chromatography, High Pressure Liquid; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005748:Gastric Fundus / Q000378:metabolism*; D066298:In Vitro Techniques; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011810:Quinoxalines / Q000494:pharmacology*; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects*; D013552:Swine
chemical_list: D000316:Adrenergic alpha-Agonists; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D011810:Quinoxalines; D018341:Receptors, Adrenergic, alpha-2; D000068438:Brimonidine Tartrate; D019001:Nitric Oxide Synthase; D000109:Acetylcholine