Autoregulation of gastric blood flow and oxygen uptake

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Abstract
This experiment studied whether the ability of the stomach to autoregulate blood flow and O2 uptake is altered by sympathetic denervation. Blood flow, O2 extraction, local arterial pressure and venous pressure were continuously monitored in sympathetically innervated and denervated autoperfused dog stomach preparations. As perfusion pressure was reduced in increments from 120 to 20 mmHg in innervated preparations, blood flow and O2 uptake decreased while O2 extraction and vascular resistance increased. Reductions in perfusion pressure in denervated preparations resulted in a decrease in blood flow, O2 uptake, and vascular resistance, whereas O2 extraction increased. The ability of the stomach to regulate blood flow and O2 uptake was significantly improved after denervation, i.e., vascular resistance decreased and O2 uptake remained relatively constant when arterial pressure was reduced. O2 uptake in denervated stomachs was generally higher than that in innervated stomachs. Autoregulation of gastric blood flow therefore appears to be improved by denervation. The better autoregulation observed after denervation may result either from a reduction in sympathetic tone and/or the increase in gastric O2 demand.