GABAA/benzodiazepine receptors in the dorsal periaqueductal gray mediate the panicolytic but not the anxiolytic effect of alprazolam in rats.

GABAA/benzodiazepine receptors in the dorsal periaqueductal gray mediate the panicolytic but not the anxiolytic effect of alprazolam in rats.
Behav Brain Res. 2019 Feb 12;:
Authors: Frias AT, Fernandes GG, Zangrossi H
Abstract
Although the etiology of panic disorder (PD) remains elusive, accumulating evidence suggests a key role for the dorsal periaqueductal gray matter (dPAG). There is also evidence that this midbrain area is critically involved in mediation of the panicolytic effect of antidepressants, which with high potency benzodiazepines (e.g. alprazolam and clonazepam) are first line treatment for PD. Whether the dPAG is also implicated in the antipanic effect of the latter drugs is, however, still unknown. We here investigated the consequences of blocking GABAA or benzodiazepine receptors within the dPAG, with bicuculline (5 pmol) and flumazenil (80 nmol), respectively, on the panicolytic and anxiolytic effects of alprazolam (4 mg/kg). Microinjection of these antagonists fully blocked the anti-escape effect, considered as a panicolytic-like action, caused by a single systemic injection of alprazolam in male Wistar rats submitted to the elevated T-maze. These antagonists, however, did not affect the anxiolytic effect of the benzodiazepine on inhibitory avoidance acquisition and punished responding, measured in the elevated T-maze and Vogel conflict tests, respectively. Altogether, our findings show the involvement of GAB...

Source: Behavioural Brain Research - February 12, 2019 Category: Neurology Authors: Frias AT, Fernandes GG, Zangrossi H Tags: Behav Brain Res Source Type: research