Footshock sensitivity of rats after adrenalectomy and glucocorticoid treatments

The threshold of flinch-jump response to electric footshock was measured after adrenalectomy (ADX) in male albino rats. The ADX-rats showed higher threshold from the 2nd to 6th postoperative days than the sham-operated animals. Daily subcutaneous administration of 100 micrograms/100 g b.w. corticosterone (CS) led to restoration of the footshock sensitivity of ADX-rats. The same effect was observed following dexamethasone (DEX) treatment. DEX but not CS administration resulted in a decrease of the footshock sensitivity in the sham-operated rats. On the 9th and 18th days after adrenalectomy, in contrast to the early postoperative period, the threshold for footshock sensitivity was significantly lower than in sham-operated controls. It is suggested that an excess release of endogenous opiates from the pituitary are involved in the changes of pain threshold under the conditions studied.