Influence of nitric oxide donors and of the alpha sub(2)-agonist UK-14,304 on acetylcholine release in the pig gastric fundus

• Published in: Neuropharmacology Vol. 40; no. 2; pp. 270 - 278
• Main Authors: Leclere, P G, Lefebvre, R A
• Format: Journal Article
• Language: English
• Published: 01.01.2001
• ISSN: 0028-3908

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 sub(2)-adrenoceptor agonists can modulate acetylcholine release from cholinergic neurones. After incubation of the tissues with [ super(3)H]-choline, basal and electrically induced release of tritium and [ super(3)H]-acetylcholine were analyzed in a medium containing physostigmine (10 super(-5) M) as well as atropine (10 super(-6) M). The NO synthase inhibitor L-N super(G)-nitroarginine methyl ester (3x10 super(-4) M), and the NO donors sodium nitroprusside (10 super(-5) M) and 3-morpholino-sydnonimine (10 super(-5) M) did not influence the basal release nor the electrically evoked release, indicating that NO does not modify [ super(3)H]-acetylcholine release. The alpha sub(2)-adrenoceptor agonist UK-14,304 (10 super(-5) M) significantly inhibited the electrically evoked release of [ super(3)H]-acetylcholine, and this effect was prevented by the alpha sub(2)-adrenoceptor antagonist rauwolscine (2x10 super(-6) M), suggesting that presynaptic alpha sub(2)-adrenoceptors are present on cholinergic neurones of the pig gastric fundus.