Influence of sumatriptan on gastric fundus tone and on the perception of gastric distension in man

Background-In animals, activation of 5-HT1 like receptors causes a relaxati on of the gastric fundus through the activation of intrinsic inhibitory neu rones. Aims-To investigate the effect of sumatriptan, an agonist at enteric neuron al 5-HT1 receptors, on fasting fundus tone and sensitivity to gastric diste nsion in man. Methods-A gastric barostat was used to study the effect of placebo and suma triptan, 6 mg subcutaneously, on basal fundic tone in healthy subjects. in addition, stepwise isobaric and isovolumetric gastric distensions were perf ormed and perception was measured before and after the administration of pl acebo and sumatriptan. Results-Placebo had no significant effects on gastric tone and on perceptio n. Sumatriptan induced an immediate relaxation of the gastric fundus, refle cted by an intragastric volume increase of 209 (39) mi (p<0.0005). After su matriptan, intragastric pressures at the thresholds for perception or disco mfort were not significantly altered. However, the intragastric volumes and the corresponding calculated wall tensions at perception and discomfort th resholds were significantly increased. Conclusions-Administration of the 5-HT1 receptor agonist sumatriptan induce s a relaxation of the gastric fundus in man, allowing larger intragastric v olumes before thresholds for perception or discomfort are reached. The effe cts of sumatriptan on the gastric fundus may have therapeutic potential in the treatment of patients with functional dyspepsia.