Experimental Study of Gastric Ulcer

Serotonin Ulcer

Abstract

Although many theories on the genesis of gastric ulcer have been advocated, an authorized theory has not been shown. Since MacDonald reported that patients suffering from Carcinoid were often complicated with gastric ulcers, it has been supposed that hyperserotonemia of them plays some role in ulcer formation.
In order to clarify the genesis of ulceration, 380 Wistar female rats weighing approximately 150g were sacrificed in this experiment. They were deprived of food for 24 hours before the experiment, but were given free access to water. Animals were injected 20mg/kg of Sero tonin Creatinin Sulphate once daily and then killed after 30min 1, 2, 4, 6, 12, 24 and 48 hours.
Results:
1) pH of gastric content measured by Tokyo pH test paper showed a significant rise comparing with that of control group.
2) The volume and the acidity of gastric juice were also measured. The former showed a conspicuous decrease, while the latter showed the same tendency as pH.
3) Congestion, petechien, erosions or ulcers were developed gradually on the mucous membrane of the stomach.
4) Ulcer formation was observed in 16% of treated animals after 4 hours and 65% of them after 12 hours.
5) The amount of serotonin in the glandular stomach was measured by Udenfriend's method in 119 rats. It increased to maximum after 2 hours with the average of 6.2μg/g and then decreased gradually.
6) The amount of blood Serotonin was measured by Udenfriend's method in 27 rats. It increased to maximum after 2 hours with the average of 0.504μg/ml and then decreased gradually as observed in the glandular stomach.
7) The ulcers were observed along the greater curvature of the glandular stomach and necrosis of mucous membrane, partial destruction of muscularis mucosa, congestion, bleeding and edema in submucosa were observed histologically. However it was interesting that not all of tissues fell into necrosis, but some part of the structure of the gland remained without any lesions. From a pathological point of view, it seems to be ascribed to circulatory disturbance.
Through the observation of Serotonin ulcer, it should be concluded that the destruction of the tissue is caused from regional anoxia which is considered to be related to vasoconstrictive action of Serotonin, but it has no relation to gastric acidity.