Oxygen uptake as a determinant of gastric blood flow autoregulation.

Autoregulation of blood flow in the denervated, autoperfused dog stomach was studied before and during local intraarterial infusion of histamine. Histamine caused an increase in gastric blood flow and oxygen uptake. The increased oxygen uptake was due entirely to an increased blood flow, ie, oxygen extraction was not altered by histamine infusion. When oxygen uptake by the stomach was less than 2.0 ml/min/100 g, there was no evidence of blood flow autoregulation, while an oxygen uptake greater than 4.0 ml/min/100 g was consistently associated with blood flow autoregulation. The data indicate that histamine enhances the ability of the stomach to autoregulate its blood flow. This effect appears to be due to histamine's influence on gastric oxygen uptake.