THE ACTION OF SOME HUMORAL AGENTS ON THE HORSE INTESTINE

Abstract

The actions of adrenaline, acetyl choline, histamine and posterior pituitary extract on the intestine of the horse have been investigated. The Magnus preparation and a perfusion technique were used. The perfusion method is described in detail.Propulsive movements of the horse ileum were only produced when the perfusion fluid contained red blood cells. The cat ileum performed propelling movements when perfused with Tyrode's solution.In the horse ileum both oral and aboral propulsion occurred, aboral propulsion predominating. The small colon did not propel its contents even when perfused with blood.Excepting adrenaline, the various humoral agents gave similar effects on the Magnus preparation and on the perfused bowel. Adrenaline produced a rise in tone with little change in the rhythmic contractions in isolated strips of ileum, Tyrode‐perfused ileum and isolated strips of the circular muscle of the large intestine; whereas it inhibited the movements of the blood‐perfused ileum and small colon. Acetyl choline and histamine caused a rise in tone and usually increased the rate of rhythmic contractions. Posterior pituitary extract produced little effect on the various preparations of intestine.