A Mineralocorticoid-Dependent Effect of Prestress on Avoidance Responding in Rats
Rats made more free-operant avoidance responses if they were given a brief prestress 30 min before the test than if they were undisturbed before the test. This effect of prestress occurred in normal rats whether foot shock, air blast, or simple handling served as the prestress. The effect did not, however, occur in adrenalectomized rats. The effect also did not occur in intact rats who were maintained on 1.5% NaCl drinking fluid, a procedure which is known to inhibit mineralocorticoid secretion. Injection of mineralocorticoid, in either adrenalectomized rats or intact NaCl-maintained rats, renewed the effect of prestress and had no effect on the subjects' response rates in sessions not preceded by prestress. Prestress completed only 1 min, rather than 30 min, before the session had a different type of effect on avoidance responding, and this effect was not abolished by adrenalectomy. It is concluded that the presence of mineralocorticoid is required for the development of a particular delayed behavioral reaction to environmental disturbance.
prestress, avoidance behavior, adrenalectomy, mineralocorticoid, delayed response, rat model, Life Sciences
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