Microneurographically Determined Muscle Sympathetic Nerve Activity Levels Are Reproducible in Insulin-Dependent Diabetes Mellitus

Our objective was to determine whether microneurographically determined muscle sympathetic nerve activity (MSNA) levels are equally reproducible in control and insulin-dependent diabetes mellitus (IDDM) subjects. We used a retrospective review of MSNA levels in 14 IDDM and 16 control subjects who had at least two microneurographic studies in the last 8 years in our laboratory. Results showed mean MSNA levels were lower in IDDM (9.2 ± 1.2 bursts/min) than in control subjects (16.8 ± 1.7 bursts/min) (p < 0.002) but mean within individual MSNA coeffients (IDDM: 47 ± 8%; controls 30 ± 5%) and ranges of variation (IDDM: 6.6 ± 1.9; controls: 7.5 ± 1.9 bursts/min) did not differ between IDDM and control subjects. Thus, microneurographically determined MSNA levels are equally reproducible in IDDM and controls subjects. These results confirm and substantiate our previous findings of diminished MSNA in IDDM subjects.