Central catecholamine and peripheral noradrenaline depletion: effects on one-way trace-conditioning.

The present study evaluated the differential contributions of the central and peripheral catecholaminergic systems in aversive learning using trace-conditioning procedure. Twenty-seven male Wistar rats were randomly assigned to one of the three groups: central drug and peripheral saline (CDPS) injections, central saline and peripheral drug (CSPD) injections, and central saline and peripheral saline (CSPS) injections. Results showed that: (1) the rate of acquisition and the overall avoidance responses for the drug treated groups was significantly poorer than the control group; (2) there was no significant difference in performance between the two drug treated groups; and, (3) neither central nor peripheral catecholamine depletion had a significant effect on the secretion of plasma corticosterone. The findings failed to confirm the hypotheses (1) that central CA depletion is more detrimental than peripheral NA depletion, (2) that plasma 11-OHCS plays a mediating role in the acquisition of avoidance and escape responses in rats depleted of catecholaminergic systems.