Mazindol effects on the salivary and gastric acid secretory mechanisms

Abstract

The effects of mazindol on the salivary secretion of dogs was investigated. Mazindol (2 mg/kg, i.v.) decreased the volume and pressure of salivary secretion induced by either chemical (carpronium) stimulation or electrical nerve stimulation. It also reduced spontaneous salivary secretion. Secretion velocity in the mazindol treated group was significantly less than in the physiological saline administered control group at 4 to 6 min after injection. Saline and mazindol produced no significance differences in Na⁺, Cl^- or K⁺ concentrations in the saliva or serum. Thus mazindol inhibition of salivary secretion was not caused by ion transport. The existence of some other inhibitory mechanism is suggested. The effects of mazindol on the peripheral and central control of gastric acid secretion was also investigated in rats. Gastric acid secretion induced by direct application of cholinergic agents on oxyntic cells was not affected by mazindol. Gastric acid secretion induced by insulin and/or 2-DG, on the other hand, was markedly inhibited by intra-hypothalamic injection or systemic (i.v.) injections of mazindol. Electroosmotic mazindol mimicked the effects of glucose in the lateral (inhibition) and ventromedial (excitation) hypothalamus. The results suggest that the inhibitory effects of mazindol on salivary secretion may be through the hypothalamic feeding control centers. Mazindol also directly affected gastric acid secretory neurons in the lateral hypothalamus. It might thus be expected to be effective in the treatment of obesity.