[Muscle sympathetic nerve activity in patients with spinocerebellar degeneration without orthostatic hypotension].

Muscle sympathetic nerve activity (MSNA) was compared in 6 patients (age; 45-76 years old, 3 males and 3 females) with spinocerebellar degeneration (SCD) without orthostatic hypotension (OH) and in 10 (age; 38-78 years old, 3 males and 7 females) with other neurologic disorders (controls). MSNA was elicited from the peroneal nerve at the resting recumbent position by using a microneurographic method. MSNA, heart rate (HR) from the electrocardiogram and mean blood pressure (MBP) measured by Finapres were recorded simultaneously at rest and during the head-up tilting at 45 degrees. Although there were no significant differences in MBP and HR between both groups, burst rate (bursts per minute) and burst incidence (bursts per 100 heart beats) of MSNA in SCD patients were significantly decreased as compared with controls (p < 0.01). During the head-up tilting, responses in MBP and MSNA showed a tendency to decrease in SCD patients. We concluded that the sympathetic noradrenergic system might be potentially impaired in SCD patients without OH.