Studies on the Role of Renal Sympathetic Nervous System in the Pathogenesis of Ischemic Acute Renal Failure

Kidneys are an abundantly innervated internal organ and the renal sympathetic nerve plays an important role in regulating body fluid volume and blood pressure via the modulation of renal functions. Here we summarized the relationship between the renal sympathetic nervous system and ischemia/reperfusion-induced acute renal failure (ARF). To clarify changes in the renal sympathetic nervous system during ischemia and reperfusion, we determined renal sympathetic nerve activity, renal interstitial norepinephrine (NE) levels and renal venous plasma NE levels. Results indicated enhanced renal sympathetic nerve activity during ischemia, accompanied by increases in renal interstitial NE level during ischemia and after reperfusion, and NE overflow in the renal vein after reperfusion. Taken together, it seems likely that the renal sympathetic nervous system is enhanced during ischemia and after reperfusion. We next demonstrated that renal denervation or a ganglion blocker markedly overcame the deterioration in renal function and tissue injury induced by ischemia/reperfusion and markedly suppressed NE overflow from renal sympathetic nerves after reperfusion. In addition, the administration of selective α 1-adrenoceptor antagonists significantly attenuated ischemia/reperfusion-induced ARF, but had no effect on the elevation of renal venous plasma NE levels after reperfusion. These results suggest that NE excessively released from the postischemic kidney is involved in the pathogenesis of ischemic ARF, probably acting on the postsynaptic