Gastric arterio-venous shunts. An investigation using a dye dilution technique.

The function of gastric submucosal A-V shunts has been investigated in dogs by the injection of a bolus of dye into the arterial side of the gastric circulation and its subsequent collection from the veins so that a dilution curve is obtained of its passage across the gastric vascular bed. Evidence of shunt activity has to be taken as a rapid transit time or double peak curves. Results suggest that under basal conditions evidence of functional A-V shunts has been found in some animals. Histamine appears to close shunts if they are open and divert blood through other slower channels. Adrenaline, vagal stimulation, vagotomy, and hepatic anoxia have not been found to have any effect on shunt activity. No evidence has been found to support the view that shunts respond in a uniform manner to control mucosal blood flow.