Effect of atropine and physostigmine on the histamine induced gastric secretion of dog.

Effect of atropine and physostigmine (0. I mg/kg of each) on histamine (0.06 mg/kg) induced gastric secretion in dogs with gastrostomy was investigated. It was observed that atropine diminished the volume, free and total acidities of gastric secretion, whereas, physostigmine raised the acidity but diminished the volume of gastric secretion possibly, due to increased motor activity of the gut. There was no variation in the total chloride in either case. It was concluded that most likely the parietal gastric cells possess a persistent tonic activity which is essential for the maximum response to histamine. The tonic activity of parietal cells is dependent on the parasympathetic innervation and was thus depressed by atropine and augmented by physostigmine, thereby. modifying the response of histamine.