A pharmacological approach to the nature of the autoregulation of the renal blood flow

Abstract

The phenomenon that the renal blood flow does not follow the increase in blood pressure but stays almost constant is defined in the renal physiology as the autoregulation of the renal blood flow. Concerning its mechanism, however, very little is yet known, but many theories have been presented. Meanwhile, the concept of the mediator in the regulation of the peripheral circulation was introduced in the physiology of circulation. Recently Berne1) assumed that adenosine acted as the mediator in the coronary circulation. This supposition has proved to be quite possible from the evidence gained in our laboratory2). As for the skeletal muscle, however, Imai et al.3) thought that the regulation of circulation might not be mediated by adenosine because the skeletal muscle tissue contained too little adenosine after a period of ischemia. The analogous data and conclusion were also presented by GERLACH et al. concerning the tissue of kidney4-5). One of the present authors found that dipyridamol decreases the renal blood flow6). Further study in this laboratory revealed that the renal vasculature exhibits a distinctly remarkable feature: adenosine and AMP constrict the renal artery instead of dilating it as in the coronary, femoral or mesenteric arteries. Dipyridamol, characterized as the potentiator of the vascular action of adenosine and the adenine nucleotides, exhibits the same type of vascular action with adenosine and AMP. Hence appears the new perspective that this substance can be useful as a tool in analyzing the physiological role of the adenyl compounds in different tissues. A development of the investigation along this line revealed some clue to the understanding of the regulatory mechanism of the renal blood flow with special reference to the effect of adenosine. © 1966, PHYSIOLOGICAL SOCIETY OF JAPAN. All rights reserved.