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Biomedical subjects

G Bertaccini

Publications and source records attributed to G Bertaccini.

At least 199 records · Page 11Linked to original sources

Action of bombesin on the motility of the stomach.

1. The tetradecapeptide bombesin was tested for its activity on the stomach in rats, dogs and men. On the rat stomach bombesin displayed a striking spasmogenic activity apparently independent from the autonomic nervous system. 2. In the dog the peptide was spasmogenic on the denervated Heidenhain pouch and the antrum. The inhibitory activity predominated on the innervated stomach and body fundus. 3. In man the peptide exerted a contracting effect on the antrum and the pylorus and an inhibitory effect on the stomach body and the fundus. In vitro studies performed on human stomach isolated strips showed a constant stimulant effect. 4. Apparently bombesin has a direct effect on the in situ rat stomach and on the isolated preparations, whereas it has an indirect effect on the other in situ innervated preparations.

Adult↗

[Spasmolytic effect of mebeverine on the gastrointestinal motility].

Mebeverine, N-ethyl-4'-[1-methyl-2-(4-methoxyphenyl)ethylamino] butyl-3,4-dimetoxybenzoate, was studied for its inhibitory effect on the motility of the gastrointestinal tract in vivo and in vitro. In both cases its activity was more evident on the hypermotility induced by some common physiological spasmogenic agents than on basal motility. In various tests it was ascertained that mebeverine was able to inhibit the stimulant actions of all the drugs employed, both those acting on specific receptor sites such as histamine and acetylcholine, and those acting directly on the smooth muscle such as substance P, physalaemin etc. This backs up the suggestion of a nonspecific miotropic effect of mebeverine. This compound has the same spasmolytic action at different levels of the gastrointestinal tract and is decisively stronger than papaverine. The lack of remarkable side-effects in the tests which were carried out in vivo with decisively active doses on the gastrointestinal motility and the good inhibitory effect on human isolated strips of the gastrointestinal tract suggest that mebeverine may be useful in the treatment of clinical morbid conditions characterized by hypertone or hypermotility of the gastrointestinal tract.

Animals↗

Gastrin release by bombesin in the dog.

1 The intravenous infusion of bombesin produced in intact dogs and, more strikingly in dogs provided with gastric fistulae a sharp increase in plasma levels of immunoreactive gastrin and at the same time a stimulation of gastric acid secretion. Gastrin response was correlated with the dose of bombesin from approximately 0.1 mug kg(-1) h(-1) (threshold) to 1 mug kg(-1) h(-1) (maximum gastrin release).2 Atropine and metiamide reduced or inhibited gastric acid secretion stimulated by bombesin, but did not affect the rise in gastrin levels.3 Acidification of the whole stomach or of a perfused antral pouch caused a reduced or delayed response to bombesin. However, the inhibitory effect of acidification could be surmounted by prolonging the duration of bombesin infusion.4 Antrectomy greatly reduced the rise in gastrin levels and the increase in acid gastric secretion produced by bombesin, but left unaffected the gastric secretagogue effect of pentagastrin.5 It is concluded that bombesin is a potent releaser of gastrin from the antral mucosa.6 The possible influence of the renal effects evoked by bombesin in the dog on the gastrin response to the polypeptide is discussed.

Animals↗

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

1. 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 (mug/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 mug/kg) or by intravenous infusion (up to 10 (mug/kg)/hour). An irregular increase in acid output was observed only following rapid intravenous injection and this was of doubtful significance.4. The mechanism of the secretagogue action of bombesin on the dog stomach is discussed.

Animals↗