The effect of electro-acupuncture stimulation on rhythm of autonomic nervous system in dogs

Effects of electro-acupuncture (EA) stimulation on the rhythm of the autonomic nervous system in dogs were studied. Six healthy beagles were used in this study. Each dog was separately kept in a cage, and repeatedly exposed to light for 12 hr and dark for 12 hr alternately. Fixed subject dogs were stimulated by use of 5-V, 250-musec, 2-Hz biphasic square pulses for 15 min at the Xuan Shu (GV-5) and Bai Hui (GV-20) points on the spine. After EA stimulation, electrocardiogram was recorded for 24 hr. From the electrocardiogram data, the heart rate (HR), coefficient of variation in the R-R intervals (CVRR; index of autonomic nervous activity), power of high frequency component (HF; index of vagal nervous activity), and ratio of powers of the low and high frequency components (LF/HF; index of sympathetic nervous activity) were obtained. Cosinor analysis demonstrated that these indices exhibited a significant rhythmicity (P<0.05), irrespective of EA stimulation. In LF/HF, EA stimulation advanced the acrophase (from 22:55 to 21:33, P=0.012), and elevated the midline-estimating statistic of rhythm (from 0.653 to 0.725, P=0.006). However, there was no significant difference in HR, CVRR, or HF. In conclusion, EA stimulation markedly influenced the rhythm of sympathetic nervous system in dogs.