EFFECT OF GRADED MECHANICAL ISCHEMIA ON OXYGEN-TENSION AND ELECTRICAL POTENTIAL IN CANINE GASTRIC-MUCOSA - NEW EXPERIMENTAL-MODEL

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 73  (1) , 84-88
Abstract
O2 tension and potential difference were measured in the gastric mucosa of anesthetized dogs with an ultramicroelectrode technique while total blood flow and arteriovenous O2 content difference were measured. In the control period, measurements were: gastric blood flow, 102.4 .+-. 3.0 ml/min per 100 g tissue; calculated O2 consumption, 2.4 .+-. 0.1 ml/min per 100 g of tissue; intracellular O2 tension, 15.0 .+-. 0.6 mm Hg; and intracellular potential difference, -50.8 .+-. 1.5 mV. When gastric blood flow was reduced 50% by tourniquet ischemia, O2 tension decreased 20% (P < 0.05) but electrical potential and O2 consumption did not change. When blood flow was reduced 75%, O2 tension and potential difference decreased significantly, 60% and 35%, respectively, but O2 consumption was unchanged. Zero blood flow reduced O2 tension, electrical potential and total O2 consumption to zero; release of the arterial tourniquet allowed them to return to control levels. The critical O2 tension, at which the electromotive force generated by the gastric mucosal cells was reduced, averaged 9 mm Hg. Safety factors probably exist in the gastric circulation which permit a 60% reduction in total gastric blood flow to occur before an insufficiency of intracellular O2 begins to limit cellular metabolism within the mucosa.

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