title: Influence of ethanol dependence and methionine enkephalin antisense on serum endomorphin-1 and methionine enkephalin levels.
abstract: BACKGROUND
  Opiate peptides are involved in the physical dependence on ethanol. Levels of methionine enkephalin (MEnk), for example, are affected by ethanol. No study on the effect of ethanol on endomorphin, the endogenous ligand for the mu-opiate receptor, has yet been conducted.
  
  
  METHODS
  We examined the effect of ethanol ingestion on serum endomorphin (EM)-1 and MEnk levels. We also determined the effect of antisense directed at MEnk on serum levels of EM-1 and MEnk.
  
  
  RESULTS
  Serum EM-1 levels steadily decreased about 20% during 56 days of ethanol ingestion in liquid feed, whereas a similar decrease in serum MEnk levels was not statistically significant. Serum MEnk levels decreased about 20% by 48 hr after antisense injection and then returned to baseline, whereas serum EM-1 levels increased by about 80% and remained elevated for about 2 weeks. In mice not treated with antisense or alcohol, there was no correlation between the serum levels of EM-1 and MEnk.
  
  
  CONCLUSIONS
  These results show that serum levels of EM-1 are decreased by physical dependence on ethanol and that this effect is not directly mediated through MEnk.
authors.affiliation: GRECC, Veterans Affairs Medical Center-St. Louis and Saint Louis University School of Medicine, Division of Geriatrics, Department of Internal Medicine, St. Louis, Missouri, USA. bankswa@slu.edu
authors.forename: William A
authors.initials: WA
authors.lastname: Banks
authors.forename: Vijaya B
authors.initials: VB
authors.lastname: Kumar
authors.forename: John E
authors.initials: JE
authors.lastname: Morley
mesh_terms: D000437:Alcoholism / Q000097:blood*; D000818:Animals; D004744:Enkephalin, Methionine / Q000097:blood*; D000431:Ethanol / Q000008:administration & dosage*; D051379:Mice; D009842:Oligopeptides / Q000097:blood*; D012646:Self Administration; D013997:Time Factors
chemical_list: D009842:Oligopeptides; C105293:endomorphin 1; D000431:Ethanol; D004744:Enkephalin, Methionine