Effects of alcohol on the synthesis and expression of hypothalamic peptides

Studies aimed at analyzing the deleterious effects of excess alcohol in the brain have revealed structural alterations that are often associated with functional and behavioral disturbances. Among the neuronal damage related t o prolonged alcohol exposure, alterations in the synthesizing capabilities and levels of expression of neuroactive peptides have been increasingly rep orted. Actually, such changes frequently represent the sole repercussion of acute and short-term exposure to ethanol. This review gathers the existing data on the effects of ethanol exposure on the synthesis and expression of hypothalamic peptides. Amid those that can act both as neurotransmitters a nd neurohormones, we allude to vasopressin, corticotropin-releasing hormone , thyrotropin-releasing hormone and pro-opiomelanocortin and related peptid es produced by paraventricular, supraoptic and arcuate neurons. With respec t to peptides that act exclusively as neurotransmitters, we address the eff ects of alcohol on vasoactive intestinal polypeptide, gastrin-releasing pep tide, somatostatin and vasopressin synthesized by suprachiasmatic neurons. Hypothalamic neurons that produce peptides that act as neurotransmitters ar e supposed to be modulated primarily by influences exerted by neuronal affe rents, whereas those producing peptides that additionally act as neurohormo nes are also regulated by peripheral stimuli (e.g., plasma levels of circul ating hormones, osmotic challenges). These peculiar features endue the hypo thalamus with characteristics that are particularly propitious to enlighten the still cryptic mechanisms underlying the ethanol effects on protein syn thesis. (C) 1999 Elsevier Science Inc.