Nitric oxide modulates release of noradrenaline in guinea-pig gastric fundus

The interaction between nitric oxide (NO) and the release of [H-3]noradrenaline ([H-3]NA) in conditions of non-activated and activated nicotinic receptors in guinea-pig gastric fundus preincubated with [H-3]NA was studied, Nicotinic receptor agonist, 1,1-dimethyl-4-phenyl-piperazinium iodide (DMPP) (100 mu M) significantly increased the resting release of [H-3]NA. NO-synthase inhibitor, N-omega-nitro-L-arginine (L-NNA) (100 mu M) significantly decreased DMPP-induced release of [H-3]NA. Field electrical stimulation (FES) (2Hz; 1 ms; 360 st) significantly increased the release of [H-3]NA above the basal revels. L-NNA significantly decreased the stimulation-evoked release of [H-3]NA. DMPP increased the stimulation-evoked release of [H-3]NA, effect which was significantly decreased by L-NNA. The data suggests that endogenous NO increases the release of [H-3]NA, evoked either by activation of the nicotinic receptors or by electrical stimulation in guinea-pig gastric fundus. (C) 2000 Elsevier Science Inc.