EFFECT OF DIFFERENT TYPES OF STIMULI ON THE COMPOSITION OF THE GASTRIC JUICE

¹ The Department of Physiology, McGill University, Montreal, Canada

1. The composition of the gastric juice varies with the stimulus, which may act selectively on different groups of cells. Two extremely different types of gastric juice are obtained (a) after subcutaneous administration of histamine, and (b) after sham-feeding or pilocarpine injection.

2. There is little difference in the total chloride concentration and the total acidity of the gastric secretion provoked by sham-feeding as compared with that provoked by histamine. In the secretion produced by pilocarpine the total acidity is markedly lower and the concentration of total chloride a little lower than with the first two stimuli. At times practically all the chloride present is in the form of HCl.

3. These slight variations in the total chloride may be due (a) to contamination of the parietal secretion with varying amounts of fluid less rich in chloride, secreted by groups of cells other than the parietal, or (b) to a less extent to changes in the concentration of chloride in the blood plasma.

4. Under the influence of any one stimulus, the gastric glands produce a secretion in which the acidity parallels more or less closely the total chloride concentration; but as soon as a new stimulus is superimposed, or at the end of the secretory period, there is an alteration in the activity of different cellular groups, and a dissociation of the two curves may occur.

5. Since the volume of secretion and the concentration of total chloride vary little with different stimuli, whereas the organic content may be ten to twenty times more than the minimum, it is therefore concluded that the greatest part of the chloride and of the fluid of the gastric juice is produced by the parietal cells.

I am greatly indebted for much helpful criticism to Professor B. P. Babkin, under whose direction this work was carried out.