[Effect of a tryptophan lead on the swine adrenal cortex reactivity and behavioral response to stress]

Behaviour and plasma corticosteroid levels were investigated in pigs preloaded with 50 to 200 mg/kg 1-tryptophan. The treatment did not influence reactions to frustation and had no effect on continuous avoidance responding. However the adrenal response to the stress of new environment concomitant with delivery of unavoidable shocks was decreased (fig. 1), as well as the behavioural response to a fear signal superimposed on a continuous avoidance paradigm (fig. 2). These results point out relatively specific psychotropic effects of a tryptophan load in pigs.