Sympathetic activity is increased in polycystic kidney disease and is associated with hypertension

Hypertension is common in patients with polycystic kidney disease (PKD). Th is study addresses the hypothesis that sympathetic activity is enhanced in hypertensive PKD patients, not only when renal function is impaired but als o when renal function is still normal. Muscle sympathetic nerve activity (M SNA, peroneal nerve), plasma renin activity (PRA), heart rate, and BP were studied in PKD patients with normal and with impaired renal function and in matched controls. In hypertensive patients with normal renal function, MSN A and mean arterial pressure (MAP) were higher than in normotensive patient s (23 +/- 5 versus 15 +/- 7 bursts/min; 110 +/- 10 versus 90 +/- 3 mmHg; P < 0.05), whereas PRA and heart rate did not differ. In PKD with chronic ren al failure (CRF) (creatinine clearance rate, 39 <plus/minus> 19 ml/min), MA P, MSNA and PRA were higher than in controls (resp, 116 +/- 7 versus 89 +/- 9 mmHg; 34 +/- 14 versus 19 +/- 9 bursts/min; 405 [20 to 1640] versus 120 [40 to 730] fmol/L per see; all P < 0.05). Heart rate in PKD CRF did not di ffer from controls. MSNA correlated with MAP (r = 0.42; P = 0.01) and age w ith MSNA (r = 0.45; P < 0.01). Regression line of age and MSNA in patients was steeper than that in controls. This study indicates that MSNA is increa sed in hypertensive PKD patients regardless of renal function. The data sup port the idea that sympathetic hyperactivity contributes to the pathogenesi s of hypertension in PKD.