Further evidence for the unimportance of renal autoregulation1

Journal/Book: Am. J. Physiol. 201(3): 495-498; 1961. 1961;

Abstract: Department of Physiology and Biophysics University Medical Center Jackson Mississippi Received for publication 31 March 1961. 1 This investigation was aided by research grants from the National Heart Institute and the Mississippi Heart Association. 2 Fellow of the National Institutes of Health. Previous experiments from this laboratory indicated that normal kidneys may not have significant intrinsic ability to autoregulate their blood flow when renal arterial pressure is varied. However in these earlier studies the renal blood flow was less than that generally accepted as normal and there was a possibility that the renal circulation had not been completely isolated. This could have resulted in extrarenal blood flow during the pressure-flow study. In the present experiments renal blood flows were in the normal range at all pressure levels. This difference was achieved by rendering the animals areflex prior to the laparotomy. The pressure-flow relationship was studied under these conditions and the resulting curves were slightly concave to the pressure axis in the lower pressure range indicating only a mild degree of autoregulation approximately the same degree as that found in other tissues. However the renal blood flow still increased rapidly with each increase in perfusion pressure even in the range of so-called autoregulation. It was also shown that all the blood that passed through the perfusion system also passed through the kidney eliminating the possibility of extrarenal blood flow. ___MH

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