Inhibition of anaphylactic histamine release in vitro by GABA.

Inhibitory effect of GABA on anaphylactic histamine release in vitro is not mimicked by 2-aminoethansulphonic acid (taurine), an aminoacid unrelated to GABA neuro-transmission. Tetrodotoxin (TTX) 6 X 10(-7) M, a concentration known to block neuronal mechanism but not to modify muscle membrane and anaphylactic histamine release, strongly prevented the inhibition caused by GABA in the Schultz-Dale reaction and in anaphylactic histamine release. The inhibitory effect of GABA on anaphylactic reaction in vitro thus appears to be specific for this aminoacid and is neurogenic in nature, in that it requires integrity of neuronal mechanisms.