Anxiolytic-Like Behavioural Effects of Head Electroacupuncture in Rats Susceptible to Stress

Abstract

Aim To evaluate the behavioural effects of head electroacupuncture (EA) using the Holtzman rat model, a genetic strain showing susceptibility to stress-evoked helplessness. Methods Putative anxiolytic and antidepressant behavioural effects of head EA were investigated using the light-dark and forced swim tests, respectively. The open field test was used to investigate motor activity. A total of 28 rats were used in two experiments, each with two groups (n=7 rats each). Rats were restrained and randomised to handling only (control) or 2Hz EA on the midline head anteriorly (at Yintang) and posteriorly (at GV20) for 3 days (experiment 1) or 4 days (experiment 2). Results One day of EA did not modify behaviour in any of the tests (p>0.1); however, 2 days of 2 Hz EA treatment to the head had anxiolytic-like effects, as indicated by an improvement in ambulatory time and average velocity in the light-dark test (experiment 2). Relative to the control group, the EA group demonstrated greater ambulatory time (37.0±3.7 vs 25.2±3.6 s, p<0.05) and lower average velocity (2.73±0.06 vs 3.08±0.13 cm/s, p<0.05). However, EA treatment had no significant effects on the open field and forced swim tests in either experiment. Conclusions Two days of EA treatment using 2 Hz pulsating electrical current at midline anterior and posterior acupuncture points on the head induces behavioural effects suggestive of anxiolysis.