Role of ghrelin in the regulation of gastric acid secretion involving nitrergic mechanisms in rats

Ghrelin, an endogenous ligand for growth hormone secretagoguereceptor (GHS-R), has been identified in the rat and humangastrointestinal tract. Ghrelin has been proposed to play a role ingastric acid secretion. Nitric oxide (NO) was shown as a mediatorin the mechanism of ghrelin action on gastric acid secretoryfunction. However, there is a little knowledge about this topic.We have investigated the role of ghrelin in gastric acid secretionand the role of NO as a mediator. Wistar albino rats were used inthis study. The pyloric sphincter was ligated through a smallmidline incision. By the time, saline (0.5 ml, iv) was injected tothe control group, ghrelin (20 μg/kg, iv) was injected to the firstexperimental group, ghrelin (20 μg/kg, iv) + L-NAME (70 mg/kg,sc) was injected to the second group and L-NAME (70 mg/kg, sc)was administered to the third group. The rats were killed 3 hafter pylorus ligation; gastric acid secretion, mucus content andplasma nitrite levels were measured. Exogenous ghrelinadministration increased gastric acid output, mucus content andtotal plasma nitrite levels, while these effects of ghrelin wereinhibited by applying L-NAME. We can conclude that ghrelinparticipates in the regulation of gastric acid secretion through NOas a mediator.