Selective Anoxic Injury to Thick Ascending Limb: An Anginal Syndrome of the Renal Medulla?

Abstract

Leichtweiss et al. and Baumgartl et al. (1,2) have previously shown that the partial pressure O₂ in the tissue, as measured by platinum microelectrodes inserted into the rat or dog kidney from cortex to medulla, drops steeply in the cortico-medullary junction to values in the range of 10 to 20 mmHg in the medulla, both in vivo and during isolated perfusion. This steep cortico-medullary gradient of pO₂ in kidney tissue is the result of the medullary vascular structure and the conditions imposed by the counter-current exchange system (3) as shown in Figure 1.