Possible genetic influence on the strength of human muscle nerve sympathetic activity at rest

Abstract

Large reproducible interindividual differences in the strength of human muscle nerve sympathetic activity have been demonstrated previously without satisfactory explanation. We undertook the present study to investigate whether a genetic influence may be a factor of importance. Microneurographic recordings of sympathetic impulse traffic were made in the peroneal nerve in nine pairs of monozygotic male twins and eight pairs of age-matched male subjects without family relationship. The strength of the sympathetic activity was quantitated as number of sympathetic bursts per 100 heart beats and bursts per minute. Group mean values of muscle sympathetic activity, heart rate, and blood pressure were similar in the two groups. Intrapair differences (mean±SEM) of sympathetic activity were 5.4±1.7 bursts per 100 heart beats (1.7±0.5 bursts per minute) for the twins and 19.4±3.2 bursts per 100 heart beats (11.8±2.5 bursts per minute) for the control subjects (P