NEUROPEPTIDE MESSENGER PLASTICITY IN THE CNS NEURONS FOLLOWING AXOTOMY

Neuronal peptides exert neurohormonal and neurotransmitter (neuromodul ator) functions in the central nervous system (CNS). Besides these fun ctions, a group of neuropeptides may have a capacity to create cell pr oliferation, growth, and survival. Axotomy induces transient (1-21 d) - upregulation of synthesis and gene expression of neuropeptides, such as galanin, corticotropin releasing factor, dynorphin, calcitonin gen e-related peptide, vasoactive intestinal polypeptide, cholecystokinin, angiotensin II, and neuropeptide Y. These neuropeptides are colocaliz ed with ''classic'' neurotransmitters (acetylcholine, aspartate, gluta mate) or neurohormones (vasopressin, oxytocin) that are downregulated by axotomy in the same neuronal cells. It is more likely that neuronal cells, in response to axotomy, increase expression of neuropeptides t hat promote their survival and regeneration, and may downregulate subs tances related to their transmitter or secretory activities.