FUNCTIONAL INTERACTIONS OF GALANIN AND ACETYLCHOLINE - RELEVANCE TO MEMORY AND ALZHEIMERS-DISEASE

Galanin, a 29-amino acid neuropeptide, is the only peptide known to co exist with acetylcholine in the basal forebrain neurons which degenera te early in the progression of Alzheimer's disease. Biochemical and ne urophysiological studies demonstrated inhibitory actions of galanin on cholinergic functions. Behavioral investigations found that intracere brally administered galanin produces deficits on spatial learning and memory tasks in rats. Taken together, the current literature suggests that galanin acts as an inhibitory modulator of acetylcholine in this coexistence. Particularly in the case of Alzheimer's disease, where ch olinergic activity is severely compromised, the negative actions of ga lanin may be particularly deleterious. Recently developed galanin anta gonists may provide a novel therapeutic approach toward enhancing memo ry processes in Alzheimer's disease, by removing the putative inhibito ry actions of endogenous galanin on the remaining basal forebrain chol inergic neurons.