Expression and conditioned inhibition of fear-potentiated startle after stimulation and blockade of AMPA/Kainate and GABA(A) receptors in the dorsal periaqueductal gray
M. Fendt, Expression and conditioned inhibition of fear-potentiated startle after stimulation and blockade of AMPA/Kainate and GABA(A) receptors in the dorsal periaqueductal gray, BRAIN RES, 880(1-2), 2000, pp. 1-10
Previous work showed that the dorsal periaqueductal gray is involved in the
inhibition of fear-potentiated startle. The present study investigated the
effects of blockade and stimulation of Kainate/AMPA and GABA(A) receptors
within the dorsal periaqueductal gray on expression and conditioned inhibit
ion of fear-potentiated startle. Blockade of the Kainate/AMPA receptors enh
anced whereas stimulation of the Kainate/AMPA receptors decreased expressio
n of fear-potentiated startle. These effects do not reflect conditioned inh
ibition since this modulation was not changed by injections of Kainate/AMPA
receptor agonists or antagonists into the dorsal periaqueductal gray. Stim
ulation and blockade of GABA(A) receptors within the dorsal periaqueductal
gray neither affected expression of fear-potentiated startle nor its condit
ioned inhibition. The present results together with findings from the liter
ature indicate that glutamate in the dorsal periaqueductal gray is a critic
al substrate for the expression and modulation of fear-related behaviours.
(C) 2000 Elsevier Science B.V. All rights reserved.