Evidence of alpha-N-acetyl β-endorphin in human cerebrospinal fluid

Fabio Facchinetti, Grazia Sances, Emilia Martignoni, Innocenzo Pagani, Giuseppe Nappi, Andrea R. Genazzani

Research output: Contribution to journalArticle

Abstract

Alpha-N-acetyl-β-endorphin (Ac-β-EP) is a post-translational product of β-endorphin (β-EP) with no analgesic properties. Ac-β-EP is present in human fetal and adult pituitary gland and cross-reacts in all available β-EP assays. This study evaluates levels of Ac-β-EP in the cerebrospinal fluid (CSF) of 22 normal subjects and 15 chronic headache sufferers. Since dopamine may play a role in the acetylation process, homovanillic acid levels were also determined. After extraction and high performance liquid chromatographic (HPLC) fractionation of CSF, an immunoreactive Ac-β-EP peak was detected coeluting with reference peptide, Ac-β-EP was detectable in all but 5 normal subjects. In headache sufferers, Ac-β-EP levels were always detectable and their mean value was significantly higher than that of healthy subjects (11.6 ± 11.8 vs 3.9 ± 3.6 fmol/ml; P <0.01). Conversely, CSF β-endorphin (β-EP) concentrations were decreased in headache patients (9.8 ± 9.4 vs 15.7 ±9.7 fmol/ml; P <0.05), and as a consequence the β-EP/Ac-β-EP ration was also markedly reduced (P <0.005). No difference was observed for CSF homovanillic acid concentrations.These data demonstrate that HPLC coupled to radioimmunoassay allows the identification of low but significant amounts of Ac β-EP in human CSF. This compound represents a confounding factor when β-EP immunoreactivity is assessed by conventional methods. In headache sufferers, Ac-β-EP levels were higher than normal, whereas β-EP concentrations were lower. This finding may thus be evidence for a lability factor, possibly worsening pain susceptibility in chronic headache sufferers.

Original languageEnglish
Pages (from-to)1-5
Number of pages5
JournalBrain Research
Volume586
Issue number1
DOIs
Publication statusPublished - Jul 17 1992

Keywords

  • Acetyl β-endorphin
  • Cerebrospinal fluid
  • Endogenous opioid
  • Headache
  • High performance liquid chromatography
  • Pain

ASJC Scopus subject areas

  • Developmental Biology
  • Molecular Biology
  • Clinical Neurology
  • Neuroscience(all)

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  • Cite this

    Facchinetti, F., Sances, G., Martignoni, E., Pagani, I., Nappi, G., & Genazzani, A. R. (1992). Evidence of alpha-N-acetyl β-endorphin in human cerebrospinal fluid. Brain Research, 586(1), 1-5. https://doi.org/10.1016/0006-8993(92)91363-J