An ACTH4-9 analog enhances social attention in aging rats: a longitudinal study.

Effect of chronic treatment of the ACTH4-9 analog, Org2766, on social attention was studied longitudinally in aging rats. A 6-week treatment temporarily enhanced specific combinations of behaviors of two interacting animals. During a 6-month treatment social attention of treated animals remained at the same level, whereas control animals showed a gradual decrease. Two months after the treatment was ceased this effect on social attention was still present; moreover, the peptide-treated animals performed better in a spatial water maze task three months after the last injection. In addition, the nerve conduction velocity of the major caudal nerves and the sciatic nerve were measured; aged, peptide-treated animals preserved their conduction velocity. The present study shows beneficial long-lasting effects of the ACTH4-9 analog in aging rats on complex behavioral indices and on a physiological measure.