EFFECTS OF CHLORPROMAZINE AND BROMOLYSERGIC ACID DIETHYLAMIDE ON GASTRIC SECRETION OF ACID INDUCED BY HISTAMINE IN RATS

INHIBITORS OF HISTAMINE CATABOLISM AND THE ACTION OF GASTRIN IN THE RAT

A method is described for the partial purification of hog's antral gastrin by gel filtration and ion-exchange chromatography. Gastrin was assayed by its effect on the pH of the effluent fluid from the perfused lumen of the stomach of the anaesthetized rat. The latency of the response to gastrin given intravenously was shorter than the latency to a similar dose of histamine. The response to gastrin injected into the arterial circulation of the stomach appeared sooner than the response to gastrin injected intravenously. Iproniazid and aminoguanidine potentiated responses to gastrin. Incubation in vitro with monamine oxidase or diamine oxidase did not inactivate gastrin. Chlorpromazine and bromolysergic acid diethylamide, in doses which enhance the effects of histamine on acid gastric secretion, did not affect responses to gastrin.

Effect of amodiaquine on gastric histamine methyltransferase and on histamine-stimulated gastric secretion

1 Amodiaquine was found to be a potent inhibitor in vitro of gastric histamine methyltransferase from human and canine corpus and from pig antrum. The ID50 for the enzyme, purified from pig antrum mucosa by ultracentrifugation and chromatography on DEAE-cellulose, was 2.5 muM. 2 In six dogs with Heidenhanin pouches the maximum secretory response to histamine (40 mug/kg i.m.) was augmented by i.m. injection of amodiaquine. The augmentation depended on the dose of amodiaquine, the optimum effect (40% increase in volume of gastric juice, 80% in acid output) being achieved with 2 mg/kg. The maximum secretory response to betazole was also enhanced by amodiaquine. 3 It was suggested that amodiaquine may enhance the histamine and betazole stimulated gastric secretion by an inhibition of gastric histamine methyltransferase in vivo.

Effect of aminoguanidine, chlorpromazine and NSD-1055 on gastric secretion and ulceration in the Shay rat

Both chlorpromazine and NSD-1055 (a non-steroidal anti-inflammatory drug) markedly lower the volume and acidity of gastric contents of rats subjected to pyloric ligation (Shay technique) and reduce the degree of ulceration in the stomach. On the other hand, aminoguanidine (an inhibitor of histaminase) has no effect on acid secretion or ulceration in these animals.

Gastric secretion during pregnancy and lactation in the rat

1. Gastric acid secretion has been studied in the rat before, during and after pregnancy using different types of stomach preparation. During the same periods the histamine-forming capacity (HFC) has been determined in gastric mucosa and mammary gland.2. In rats with a whole stomach fistula interdigestive acid secretion is increased during pregnancy and lactation.3. In rats with a denervated chronic pouch secretory response to stimulation with gastrin and histamine is augmented during pregnancy and lactation.4. The histamine forming capacity (HFC) of the gastric mucosa is increased 2-3 times during the last days of pregnancy and also during lactation.5. The HFC of the mammary gland is increased 2-3 times during lactation as compared with the fully developed gland in pregnancy.