The function of the sympathetic nervous system determined by humoral factors in the maintenance hemodialysis patients

: Dialysis-induced hypovolemia in renal patients might accompany with decreased sympathetic tone and decreased baroreflex sensitivity. Present study was undertaken to elucidate the sympathetic nervous activity in terms of biogenic amines [plasma norepinephrine (NE), epinephrine (E) concentrations, dopamine-beta-hydroxylase activity (DBH) and plasma serotonin (5-HT) concentration] in 17 patients with chronic renal failure in whom renal hemodialysis were continuously performed. During pre-dialysis period, in these hemodialysis patients, heart rate, systolic blood pressure and plasma 5-HT were significantly elevated as compared with those on sex and age-matched controls; plasma NE and plasma DBH were not changed in these hemodialysis patients as compared with those in controls. After hemodialysis, increased plasma NE and increased DBH were observed in parallel with the significant weight loss. Mean blood pressure did not change after dialysis. Dialysis produced an increasing tendency of heart rate. Dialysis also produced a significant decrease in plasma 5-HT. Hemodialysis-induced weight loss was approximately 2 kg body weight after 5 hours dialysis; these patients were done 3 times dialysis during one week. However, hypotension and dizziness were not demonstrated under this condition. Present study revealed that long term maintenance hemodialysis produced increased sympathetic nervous system activity; the assumed explanation would be relevant to the simultaneous recovery of baroreflex sensitivity and sympathetic tone, because of the long-term continuous hemodialysis.