ON THE MOVEMENTS OF THE ISOLATED SMALL INTESTINE AND THE ACTION OF VARIOUS DRUGS AND EXTRACTS UPON THEM

Abstract

Alkali and Acid.—Sodium bicarbonate in concentration of ·01 per cent. to ·04 per cent. increases the tone of the intestine without altering the pendulum movements; with higher concentration the movements are inhibited. Hydrochloric acid inhibits both the tone and the movements of the intestine; the inhibition is seen with ·0005 per cent. HCL.Carbon Dioxide.—CO2 has an inhibitory action on both the tone and the movements of the intestine. If the action of CO2 is prolonged the intestine is permanently injured and eventually killed.Hyoscyamine and Hyoscine.—Hyoscyamine has a stimulating action; it can initiate the movements when they are absent. The pendulum movements are increased in size and made more regular, the tonus oscillations being partially or completely abolished. Stimulation is seen with ·001 per cent. of concentration. The action of hyoscine is similar to that of hyoscyamine, but it is weaker; ·02 per cent. being the weakest concentration having a distinct action. Both drugs inhibit the stimulation produced by pilocarpine.Cocaine.—Cocaine has a stimulating action in strength from ·001 per cent. to ·01 per cent.; with higher concentration no stimulation is seen, but a marked regularising effect then appears; with ·2 per cent. a paralysing of the intestine comes on. Inhibition to the action of pilocarpine does not occur.Choline and Neurine.—Choline produces a marked rise of tone in the isolated intestine; this occurs with concentration of 1 in 50,000; with high concentration the pendulum movements are obliterated. Atropine inhibits the action. There is also a mutual antagonism between the actions of choline and adrenaline. Neurine in its action·resembles choline, but it is more powerful; 1 in 100,000 produces an effect.Pituitary Extract.—Watery extract of the posterior lobe on the isolated intestine of the cat has the effect of raising the tone and causing the development of large tonus oscillations. The action occurs only with high concentrations; thus two glands per 100 c.c. of Ringer's solution is the weakest extract to give definite results. Alcoholic extract has no action.Suprarenal Extract.—Hemisine causes inhibition of the movements and lowering of the tone of the intestine; 1 in 10,000,000 produces a small but distinct effect.Other Extracts.—Extracts of spleen, thyroid, thymus, pancreas, liver, kidney, and brain give no definite results.Gastro‐Intestinal Contents.—Stomach contents inhibit the movements by their acidity alone. The contents of the small intestine have often a marked stimulating effect apart from, but to a considerable degree influenced by, their reaction. Extract of digesting gastric mucous membrane and of mucous membrane of small intestine, and also secretine, have when neutralised no definite action. Pancreatic secretion increases the tone. Indol inhibits the movements and lowers the tone. Bile has a similar action.