THE CARDIOVASCULAR STARTLE RESPONSE - ANXIETY AND THE BENZODIAZEPINE RECEPTOR COMPLEX

Benzodiazepine receptor (BZR) agonists are prototypic anxiolytic agent s, whereas BZR inverse agonists exert anxiogenic effects. The effects of these compounds offer a potentially important pharmacological model system to examine the central mechanisms of anxiety. In accord with i ts putative anxiogenic properties, we previously found that the BZR pa rtial inverse agonist, FG 7142, enhances the cardiovascular defensive response to a nonsignal acoustic stimulus in rats. In contrast, we fou nd in the present study that this agent attenuates both the somatic an d cardiovascular components of the acoustic startle response. BZR agon ists and inverse agonists are known to modulate the basal forebrain co rtical cholinergic system, and we consider the potential involvement o f this system in the disparate psychophysiological actions of FG 7142 and in anxiety states in general.