THE TRANSPLANTED HUMAN KIDNEY DOES NOT ACHIEVE FUNCTIONAL REINNERVATION

1. Previous histological studies have demonstrated partial reinnervati on of the human transplanted kidney. However, it remains unknown wheth er this reinnervation is of any functional significance. 2. The effect s of noradrenaline infusion (2 mu g h(-1) kg(-1)) and lower body negat ive pressure (-27mmHg) on renal haemodynamics, sodium excretion and tu bular function were investigated in 25 renal transplant recipients and 10 normal subjects. Sixteen of the transplant recipients had all been transplanted for more than 27 months, and nine had all been transplan ted for less than 2 months.3. After an overnight fast, the subjects we re water-loaded, and clearance studies were performed with a Ih baseli ne period, a Ih period with noradrenaline infusion, another 1h baselin e period, and a final 1h period with lower body negative pressure. 4. During noradrenaline infusion the relative decrease in effective renal plasma flow, glomerular filtration rate and clearance of lithium and sodium was significantly more pronounced in the long-term transplanted patients than in the control subjects. 5. Lower body negative pressur e only depressed the glomerular filtration rate significantly in the c ontrol subjects. Further, the relative decrease in effective renal pla sma flow and clearance of lithium and sodium was significantly greater in the control subjects than in the two groups of transplanted patien ts. 6. The present study thus demonstrated that in short- and long-ter m transplanted kidneys in man, supersensitivity to circulating noradre naline and an inadequate response to lower body negative pressure was present. This strongly suggests that the human transplanted kidney rem ains functionally denervated.