title: Opioid receptor ligands in human hepatic encephalopathy.
abstract: OBJECTIVE
  Opioid peptides may contribute to some of the manifestations of hepatic encephalopathy. To address the role of the opioid system in the pathogenesis of hepatic encephalopathy, three representative opioid ligands were measured in plasma and cerebrospinal fluid of patients with hepatic encephalopathy.
  
  
  METHODS
  Plasma and cerebrospinal fluid were obtained in three groups of patients: group 1: patients with hepatic encephalopathy; group 2: patients with lumbar back pain; group 3: healthy controls. Met-enkephalin, leu-enkephalin and beta-endorphin levels were measured in extracted plasma and cerebrospinal fluid samples by radioimmunoassay.
  
  
  RESULTS
  Plasma met-enkephalin levels were 656% (p<0.05) and 301% (p<0.05) and cerebrospinal fluid met-enkephalin levels were 1481% (p<0.01) and 645% (p<0.05) higher when compared to healthy control and pain control patients, respectively. Although plasma and cerebrospinal leu-enkephalin levels were elevated in patients with hepatic encephalopathy, the increases were not statistically significant. Plasma and cerebrospinal beta-endorphin levels were similar in the three study groups.
  
  
  CONCLUSIONS
  The results of this study support accumulating data on the role of the delta opioid receptor ligand met-enkephalin in the pathogenesis of hepatic encephalopathy, and provide a rationale for the use of opioid receptor antagonists in the treatment of hepatic encephalopathy.
authors.affiliation: Department of Gastroenterology, University of Ankara, Turkey. yurdaydi@dialup.ankara edu.tr
authors.forename: C
authors.initials: C
authors.lastname: Yurdaydin
authors.forename: D
authors.initials: D
authors.lastname: Karavelioglu
authors.forename: O
authors.initials: O
authors.lastname: Onaran
authors.forename: T
authors.initials: T
authors.lastname: Celik
authors.forename: M H
authors.initials: MH
authors.lastname: Yaşa
authors.forename: O
authors.initials: O
authors.lastname: Uzunalimoglu
mesh_terms: D004743:Enkephalin, Leucine / Q000097:blood* / Q000134:cerebrospinal fluid*; D004744:Enkephalin, Methionine / Q000097:blood* / Q000134:cerebrospinal fluid*; D006501:Hepatic Encephalopathy / Q000097:blood* / Q000134:cerebrospinal fluid*; D006801:Humans; D008024:Ligands; D011863:Radioimmunoassay; D011957:Receptors, Opioid / Q000378:metabolism*; D001615:beta-Endorphin / Q000097:blood* / Q000134:cerebrospinal fluid*
chemical_list: D008024:Ligands; D011957:Receptors, Opioid; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D001615:beta-Endorphin