Nitric oxide and gastric relaxation.

Pentagastrin enhanced the volume increase caused by isobaric gastric distension in conscious dogs. This effect could be abolished by inhibitors of acid secretion and mimicked by histamine. The increased compliance after pentagastrin was not affected by L-nitroarginine (L-NNA), a blocker of nitric oxide (NO) synthase. L-NNA itself reduced the volume increases caused by isobaric gastric distension. Intralipid administration into the duodenum led to a gastric relaxation sensitive to inhibition by L-NNA. The inhibitory effect of L-NNA was partially reversed by L-arginine. Pentagastrin induces a gastric relaxation via a mechanism that involves gastric secretion but not nitric oxide, whereas intraduodenal intralipid induces a gastric relaxation via a NO-dependent mechanism.