Tissue Responses to Hypoxia, Shock and Stroke

Abstract

Tissue hypoxia may occur in tissues either naturally or experimentally in association with arterial hypoxaemia, hypovol-aemic shock and so-called endotoxic shock, together with acute ischaemia caused by thrombosis, or some other form of vascular occlusion. In an attempt to distinguish between the results of hypoxia at the cellular level produced by these different causes, a comparison has been made between the response of liver on the one hand, and the cerebral cortex on the other. Both these organs are susceptible to tissue hypoxia and prolonged hypoxia of either organ will ultimately be fatal. Investigations were carried out by using microprobes sensitive to oxygen, pH and other ions and also with an optical probe which gave measurements of the intracellular redox state as judged by pyridine nucleotide fluorescence (Chance et al 1962). There have been a number of papers on the effects of hypoxia on ionic movements in brain (see Bito and Myers 1972; Dora and Zeuthen 1975) and there have been preliminary observations of the changes in liver which occur during shock as compared to hypoxia (Silver 1973; Sinagowitz et al 1973; Kessler et al 1973, 1975).