Amphetamine and tranylcypromine in an animal model of depression: Pharmacological specificity of the reversal effect

Amphetamine and tranylcypromine are structurally related chemical isomers with pharmacologically distinctive activity profiles. Since they are equimolar and structurally similar they may be used to assess the pharmacological specificity of a proposed animal model of depression. Adult male Sprague-Dawley rats were exposed to a chronic stress regimen or remained undisturbed. They were then acutely stressed with white noise. The monoamine oxidase inhibitor tranylcypromine was effective in restoring otherwise reduced stress elicited open field activity in chronically stressed rats. Amphetamine did not resemble tranylcypromine or other antidepressants, and produced a variety of effects at least some of which indicated a potential increase rather than reduction in depression consequent to chronic administration.