Central catecholamine and peripheral noradrenaline depletion by 6-hydroxydopamine and active avoidance learning in rats.

Three experiments are reported on the relation among catecholamine (CA) depletion, plasma corticosterone (11-OHCS) levels, and active aversive learning. A baseline study showed no significant relation beteen resting levels of 11-OHCS and central and/or peripheral CA depletion. On a two-way avoidance learning task, depletion of brain CAs produced a widespread learning deficit. When both central and peripheral CAs were depleted, only escape learning emerged. Similar effects occurred on a one-way task, but differences were not so marked. The findings are discussed in terms of a theory of CA-dependent cues.