The effect of an acute ethanol exposure on the rat brain POMC opiopeptide system

Endogenous peptides with a high affinity for opiate receptors located in the central nervous system have been postulated to play a role in the etiology of alcoholism or in other addictive diseases. Effects of different doses of ethanol (EtOH) at different time points post-EtOH administration on hypothalamic and hindbrain beta-endorphin-like peptide (beta-EPLP) content in male rats were measured by radioimmunoassay (RIA). A single EtOH exposure resulted in an increase in hypothalamic and a decrease in the hindbrain beta-EPLP levels. In another set of experiments, proopiomelanocortin (POMC) synthesis in the hypothalamus was measured by assaying both POMC primary transcript and mature mRNA. No changes in primary transcript or mature POMC hypothalamic mRNA were detected. Based on the results from this experiment we conclude that an acute EtOH exposure affects the rat hypothalamic POMC opiopeptide system by increasing levels of beta-EPLP and this increase in levels is not related to an increase in synthesis.