Reversal of learned helplessness by nortriptyline

Abstract

• 1.

  1. Animals exposed to inescapable stress display avoidance and escape deficits when tested in a later task situation where successful responding results in stress offset, a phenomenon termed learned helplessness. This paradigm has been suggested as an animal model of depression as it shares many of the characteristics of the human disorder.

• 2.

  2. An escape delay procedure previously shown to reveal interference effects in mice was reproduced in rats.

• 3.

  3. Using this escape delay procedure, the effects of acute and sub-acute administration of nortriptyline on learned helplessness behavior were assessed.

• 4.

  4. Four and 6 days of drug treatment reversed the escape deficits produced in animals exposed to pre-shock whereas the 0 and 2 day drug regimens were without effect.

• 5.

  5. These findings support the utility of the learned helplessness model in evaluating the potential of antidepressant agents in experimental animals.