Motor depression and head twitches induced by IP injection of GABA.

Influence of GABA onlocomotor activity and gross behavior of mice, rats, and rabbits was studied. In mice and rats, IP GABA injection produced decreased locomotor activity, but in rats and rabbits head twitches and disturbances in body balance were seen. GABA-induced head twitches were inhibited by picrotoxin, clonidine, morphine, or cyproheptadine. Our results suggest a serotonergic component in GABA-induced head twitches, but it is not the only mechanism involved in this behavior.