Effect of somatostatin on 133Xe clearance from colonic mucosa before and after local nervous blockade in unanaesthetized man.

The effect of intravenous somatostatin bolus on mucosal and submucosal blood flow in six patients with colostomies was studied with the local 133Xe clearance technique. Mucosal and submucosal blood flow decreased by 28% after somatostatin injection. After induction of local nervous blockade by infiltrating the labelled area of the mucosal membrane with lidocaine the reduction in blood flow caused by somatostatin was abolished. These observations suggest that the vasoconstrictor effect of somatostatin is mediated by neurogenic mechanisms.