Modulation of Memory by Pituitary Hormones and Related Peptides

This chapter discusses the modulation of memory by pituitary hormones and related peptides. The phenomenon of memory can be differentiated into a number of conceptual classifications according to various schemata. The memory processing involves four steps: (1) selection of some stimuli from the perceptual environment; (2) consolidation or storage into memory by some neurobiological mechanisms; (3) decay, or the eventual forgetting of information; and (4) retrieval of stored information by an equally ill-understood neurobiological mechanism. Adrenocorticotropic hormone (ACTH)-like peptides facilitates retrieval of memory in animals. This effect derives from sites of action within the central nervous system. The facilitated retrieval is transient and does not persist beyond the period of treatment. ACTH-like peptides enhance vigilance in humans. This effect also derives from sites of action within the central nervous system. ACTH-like peptides may facilitate memory storage. The chapter also reviews the evidence for specific modulatory influences, both enhancing and disrupting, of a variety of peptides. The disruptive effects of oxytocin and the facilitatory effects of vasopressin on memory suggest that when endogenous peptides are active in normal memory functioning they interact in a complex fashion.