Medial frontal lesions, postoperative treatment with an ACTH(4-9) analog, and acquisition of a win-shift spatial...

Forty adult rats of both genders were randomly assigned to one of four factorial groups and prepared with either medial frontal or sham lesions. On the day of surgery osmotic mini-pumps that had been prepared to deliver either 12.5 micrograms of ACTH(4-9) analog per 24 h or saline for the next 14 days were installed in a subcutaneous location. One month following surgery, these animals were studied in an avoidance conditioning experiment. Four to 6 months later their abilities to learn a water maze win-shift spatial strategy was investigated. The brain-damaged rats were found to be deficient on all behavioral measures examined: errors to criterion, days to criterion, and perseverative errors. Although post-neurosurgical administration of the ACTH 4-9 analog has been shown to improve behavioral recovery from brain damage in some studies, the peptide failed to improve the behaviors examined here.