Pharmacology of Fear, Induced by Periaqueductal Gray Stimulation in the Rat

Abstract

SUMMARY: The effect of drugs on escape induced by aversive stimulation of the periaqueductal gray (PAG) matter is reviewed. Strongest influences were observed with compounds influencing GABA-ergic and serotonergic neurotransmission. Activation of the 5-HT1C-receptor is an effective way towards inhibition of the aversive effect of brain stimulation. An opposite effect was obtained by stimulation of 5-HT1A and 5-HTr receptors. Dopaminergic D2-receptor activation seems to have weak enhancing effects on the stimulation induced aversive state. In view of these phannacological characteristics it is not possible to conclude that there is a straight forward parallelism between brain stimulation-induced fear and a particular anxiety disorder.