Noradrenergic and dopaminergic interactions in escape behavior: analysis of uncontrollable stress effects.

The effects of norepinephrine receptor blockade on the deficits of escape behavior induced by haloperidol and by inescapable shock were evaluated. Phenoxybenzamine, the alpha-norepinephrine receptor blocker, was found to enhance escape behavior and to eliminate the disruptive effects of both inescapable shock and haloperidol. In contrast, the beta-norepinephrine receptor antagonist, propranolol, was without effect on behavior under any of these conditions, while the dopamine-beta-hydroxylase inhibitor, FLA-63, disrupted performance. Like phenoxybenzamine, the norepinephrine receptor stimulant, clonidine, was found to eliminate the behavioral disruption produced by haloperidol. These somewhat paradoxical findings were discussed in terms of the contribution of DA-NE interactions in determining behavioral change in aversive paradigms.