Regulation of renal circulation during behavioral changes in the cat

In unanesthetized cats, implanted with electromagnetic flow probes and an arterial catheter, excitatory states were accompanied by reduction in blood flow to the intact innervated kidney: vasoconstriction was greater with increasing excitement. Natural sleep was accompanied by renal vasodilatation progressive in magnitude from the synchronized to the desynchronized phase. Changes in renal circulation were similar in direction, but somewhat smaller than changes in mesenteric circulation. In the denervated kidney no vasoconstriction occurred during emotion without motor excitement, but a delayed vasoconstriction was present during stronger excitatory states with movement. During sleep, an identical vasodilatation was observed in both the innervated and the denervated kidney. It is concluded that: renal vessels undergo constriction and dilatation during ordinary behavior and constriction is capable of decreasing renal blood flow; during emotional responses unaccompanied by muscle movement, renal vasoconstriction is entirely neurogenic, but when movements are present a humoral component may contribute; during sleep, renal vasodilatation can occur independently of neural mechanisms, probably through vascular autoregulation.