Neuropeptides, mental performance and aging.

The presence of peptidergic neuronal networks in the brain and the modulating action of neuropeptides on brain functions as evidenced by their behavioral influence in particular support the concept that the brain like the peripheral endocrine glands is an endocrine target organ which is as sensitive to treatment with neuropeptides as the peripheral glands are to pituitary hormones. Animal and human data are reviewed showing that neuropeptides related to ACTH/MSH affect motivational and attentional processes and that those related to vasopressin are involved in memory processes. Since these functions decline during aging it is postulated that a decreased bioavailability of neuropeptides in brain of elderly people is associated with specific disturbances in mental performance. Thus, the decreased mental ability of the aged may be restored by treatment with neuropeptides particularly those with little, if any, peripheral, endocrine activity, like the ACTH neuropeptide Org 2766 and the vasopressin neuropeptide DGAVP.