Behavioral effects of L-tryptophan and p-chlorophenylalanine after adrenalectomy or dexamethasone administration in rats

Effects of acute administration of L-tryptophan (L-TRP. 250.0 mg/kg, i.p.) on active avoidance conditioning and "open-field" behavior were studied in male rats after adrenalectomy of dexamethasone administration. L-TRP inhibited the acquisition and reproduction of active avoidance reaction in adrenalectomized and dexamethasone-treated rats. Moreover, L-TRP decreased horizontal locomotor activity and grooming behavior in the "open field" on adrenalectomized rats. On the contrary, p-CPA restored the active avoidance conditioning in adrenalectomized rats and rats with excess of glucocorticoids. Also, p-CPA increased the total locomotor activity and grooming behavior in the "open field" in adrenalectomized rats, but decreased horizontal locomotor activity and enhanced emotional reaction in dexamethasone-treated rats in the "open field".