Differential mechanisms involved in the anticonflict action of benzodiazepines injected into the central amygdala and mammillary body

Abstract

The present study was designed to clarify the mechanism of action of benzodiazepines (BDZ) injected into the central amygdala (ACE) and mammillary body (MB). When γ-aminobutyric acid (GABA) at doses of 30 and 70 μg, muscimol (0.01 and 0.03 μg), valproate (200 μg), atropine (20 μg) and cyproheptadine (3 μg were bilaterally injected into ACE, a significant and marked increase in the punished responses of conflict schedule was observed. These drugs injected into MB failed to increase the punished responses. In MB, only noradrenaline (NA, 20 μg) showed the anticonflict action. NA 20 μg also produced the anticonflict action in ACE. These results suggest that the mechanism of anticonflict action of BDZ is different in brain areas. The GABA-ergic, cholinergic, serotonergic and NA-ergic system sseem to be involved in the mechanism of anticonflict action of BDZ in ACE. While the NA-ergic system appears to be operative in MB.