Abstract
Effects of methylprednisolone sodium succinate, a water soluble corticosteroid, on conditioned behaviors in fixed ratio (FR 30) and fixed interval (FI 60sec.) schedules of food reinforcement, as well as in Sidman's and discriminated avoidance schedules were investigated in rats.
The effects on conditioned suppression (CER) which was developed by warning stimulus associated with electric shock in FR and FI schedules, were also observed after the steroid.
These conditioned responses did not exhibit marked change following the administration of the steroid (10-40 mg/kg). However, correct response rate increased with decreasing of total responses in discriminated avoidance schedule. Such phenomena became rather prominent 24 hours after the administration; thus the mechanism was probably caused by the inhibition of ACTH-release rather than by the direct central-action of the steroid.
