Acute vasodepressor effect in normotensive rats following extracorporal perfusion of the declipped kidney of two-kidney, one clip hypertensive rats.

Abstract

Experiments were performed to determine the extent to which the rapid normalization of arterial pressure after renal dedJpplng in chronic two-kidney, one clip renal hypertensive rats (RHR) is caused by the release of depressor agents from the kidney. Such a phenomenon would then represent a "hypotensive disturbance" of a structurally already adapted hypertensive cardiovascular system, rather than a true normalization of cardiovascular bomeostasls. Consequently a marked pressure fall was expected to occur also hi a norraotensive rat when exposed to the venous effluent from an extracorporally perfused, acutely declipped kidney of a chronically hypertensive RHR. In 10 experiments, isolated clipped RHR kidneys were perfused via an extracorporal pump perfusion circuit from conscious normotensive rats. Mean arterial pressure (MAP), heart rate (HR), and cardiac output (CO) were followed in these normotensive rats, and the values remained largely unchanged as long as the renal artery clip was left in place. Upon sudden removal of the renal dip, with the renal perfusion pressure being maintained at the hypertensive level, the MAP of the conscious, normotensive rats fell from 127 ± 2 to 85 ± 7 mm Hg (p < 0.001) within 20 minutes, and decreased to 69±7 mm Hg in 1 hour. However, the HR remained almost unchanged, despite the marked pressure fall due to a reduction of CO from 29.1 ± IS to 14.7 ± 2.5 ml/min/100 g body weight (p < 0.001). Similar extracorporal perfusions of isolated normotensive kidneys did not cause any significant changes in either MAP, HR, or CO. These findings suggest the release of powerful depressor agents from an acutely declipped kidney. The depressor agents may, at least in part, elicit their hypotensive effects by an action on the central nervous system, since the drop in pressure was not accompanied by any reflex tachycardia, which occurs when similar pressure reductions are induced by blood loss or vasodilator substances. (Hypertension 4 (suppl II): II-101-II-105, 1982)

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Cite this paper

@article{Gthberg1982AcuteVE, title={Acute vasodepressor effect in normotensive rats following extracorporal perfusion of the declipped kidney of two-kidney, one clip hypertensive rats.}, author={Gunnar G{\"{o}thberg and Stefan Lundin and Bjorn Folkow}, journal={Hypertension}, year={1982}, volume={4 3 Pt 2}, pages={101-5} }