THE MECHANISM OF DEFLATION HYPEREMIA IN THE INTESTINE

Abstract

The augmentation of arterial flow into loops of the dog''s small intestine following a period of low-pressure distention (deflation hyperemia) was associated with an augmented venous return, and exceeded in vol. the vol. reduction in the gut walls during the distention period. No significant portion of the hyperemia was due to the filling of the suddenly decompressed peripheral vascular segments. In comparing deflation hyperemia with reactive hyperemia, it was found that reactive hyperemia increased in height (maximum rate of flow) and in area (total flow excess over control) with increasing duration of ischemia, whereas deflation hyperemia did not increase with increasing duration of the distention. Cocaine applied to the mucosa of the loop usually abolished deflation hyperemia, without significantly modifying reactive hyperemia. The mechanism of deflation hyperemia was not identical with that of reactive hyperemia. These data are offered in support of the theory that distention sets up through the peripheral nervous apparatus resistance-lowering mechanisms which persist for a time after deflation.