Acupuncture has an analgesic effect in rabbits

Abstract

Rabbits were used for the study of the mechanisms of acupuncture analgesia in several laboratories over the world. Its feasibility was questioned by Galeano et al. in 2 recent papers. Here, experimental details are presented for the induction of analgesia by electroacupuncture (EA) in the rabbit. A total of 219 experiments were performed in 47 adult rabbits. Latency of avoidance response (ARL) elicited by radiant heat exposure on the skin over the snout or the tail was taken as the index of nociception, the efficacy of which was verified by the constancy of the ARL over the period of observation and the dose-dependent increase of ARL after morphine injection. EA stimulation of the Zusanli and Quenlun points in 1 hind leg for 10 min brought about an intensity-dependent increase of ARL by 127, 155 and 170% on the snout and a comparable increase on the tail in groups of rabbits receiving 0.5, 1 and 2 V EA stimulation, respectively. The increased ARL faded away exponentially after the cessation of EA with half-lives of 10, 11 and 13 min in these 3 groups of animals. The effects were partially blocked by intracerebroventricular injections of naloxone. Under optimal conditions intensity-dependent and reproducible EA analgesia can be elicited in rabbits without visible agitation or frightened responses.