Studies on the Intestinal Vasodilatation Observed after Mechanical Stimulation of the Mucosa of the Gut

Mechanical stimulation of the jejune mucosa of the cat induces a transient increase of total intestinal blood flow amounting to 30–140 per cent of control. The vasodilatation is at least partly localized to the intestinal villi. The observed blood flow augmentation cannot be abolished by autonomic denervation or blockade by atropine, α‐ or β‐blocking agents or by a cholinergic ganglionic blocking agent. However, the intestinal blood flow augmentation was completely abolished by tetrodotoxin, a nerve conductivity blocking agent, by lidocaine, a local anesthetic, and by 2‐bromo‐LSD, a 5‐hydroxytryptamine (5‐HT) receptor blocker. These results seem to suggest that the studied intestinal vasodilatation is evokedviaan intramural nervous reflex in some way dependent on the release of 5‐HT.‐The observation that bile administered into the intestinal lumen causes a prolonged intestinal vasodilatation is briefly discussed.