The actions of bombesin on gastric secretion of the dog and the rat

Abstract

Summary1. Bombesin stimulated acid secretion from the denervated fundic pouch of the dog. Whereas the concentration of hydrochloric acid in bombesin-produced juice was always higher than in control juice this did not occur for pepsin, the concentration of which remained below the basal values. The threshold dose of bombesin was 5-30 ng/kg by the subcutaneous route and 0-05-0-2 (gg/kg)/h by intravenous infusion. At low doses bombesin was more active than caerulein, even on a molar basis, and at high dose levels was as active as caerulein. In contrast to gastrin and caerulein, bombesin elicited a moderate secretory response also following rapid intravenous injection.2. The acid secretion provoked by bombesin was almost completely inhibited by atropine and reduced by approximately 50% by hexamethonium. 3. Bombesin did not stimulate acid secretion in the lumen-perfused preparation of the rat stomach when administered by subcutaneous injection (up to 10

Gastrin Release by Bombesin in the Dog

“…Previous studies (Bertaccini, Erspamer & Impicciatore, 1973) (Grossman, 1967;Bertaccini, Endean, Erspamer & Impicciatore, 1968). However, increase in plasma gastrin levels remained unchanged or was affected to a much smaller degree.…”

“…It was shown in a previous paper (Bertaccini, Erspamer & Impicciatore, 1973) that bombesin (Pyr-Gln-Arg-Leu-Gly-Asn-Gln-Trp-Ala-ValGly-His-Leu-Met-NH2), an active tetradecapeptide isolated from methanol extracts of the skin of two European discoglossid frogs Bombina bombina and Bombina variegata variegata (Anastasi, Erspamer & Bucci, 1972), displayed a potent stimulant action on secretion from the denervated fundic pouch of the dog. There was a conspicuous increase in the volume of gastric juice accompanied by an increase in total acid and pepsin outputs and in hydrochloric acid concentration.…”

Depletion of gastrin-releasing peptide(GRP) from nerves in the gastric body of rats with experimental ulcers. An immunohistochemical study.

“…The present study showed that the depletion of GRP from nerves in the pyloric antrum was not so marked as compared with that in the oxyntic area. In the rat, moreover, it has been claimed that GRP induces gastrin release from antral G cells, though it nevertheless does not eventually influence the release of gastric acid, differing from experimental results obtained using other mammalian species (BERTACCINI et al, 1973;TAKAGI et al, 1986;WALSH, 1987). This has been explained by that GRP might also stimulate the release of some endogenous substances inhibiting the gastric secretion, such as somatostatin (DUVAL et al, 1980).…”

Brain regulation of gastric secretion: influence of neuropeptides.

“…In agreement with the latter finding, bombesin administered i.v. or subcutaneously has been reported to have no influence on acid secretion in the perfused preparation of rat stomach (27), whereas bombesin is a very potent gastric acid releaser in dog or in human (28,29). The exact neuroanatomical site of bombesin action, perhaps located in structures known to affect gastric secretions and food intake or those already demonstrated to be the substrate mediating its hypothermic action (30), is presently unknown.…”