Detection of a novel immunoreactive endomorphin 2-like peptide in rat brain extracts

Erzsébet Szemenyei, I. Barna, Z. Mergl, Attila Keresztes, Z. Darula, Erzsébet Kató, Géza Tóth, A. Rónai

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

To pursue further the possible de novo biosynthetic pathway of endomorphins in rat brain we raised antibodies to endomorphin-2 conjugate in rabbits. Antiserum R1 recognized endomorphin-2 with good selectivity as compared to endomorphin-1 with a median detection value of 65.5 ± 7.5 pg/tube (n = 7), whereas R4 antiserum recognized both endomorphins with similar sensitivity. Neither antisera recognized YP-related di- or tripeptides or YGGF-related opioid sequences (enkephalins, β-endorphin, dynorphin). Using the same rat brain extraction-RP-HPLC-gradient separation paradigm as previously, antisera detected 144.6 ± 40.0 (n = 3) pg/g wet brain weight endomorphin-2-like immunoreactivity in the fraction corresponding to standard endomorphin-2 retention time and also in the fraction matching endomorphin-2-OH standard retention time (179.1 ± 30.1 pg/g). Since R1 failed to recognize authentic endomorphin-2-OH, the second immunoreactive species must be different from both endomorphin-2 and endomorphin-2-OH. Possible biosynthetic intermediates to endomorphins, synthetic YPFFG and YPWFG had retention times close to the parent endomorphin standards in RP-HPLC gradient separation profile. The former was a μ-opioid receptor agonist of medium potency in the in vitro assays (rat brain RBA&GTPγS binding and mouse vas deferens), whereas the latter was a weak μ-opioid receptor agonist with a significant δ-opioid receptorial action as well and a definite indication of partial agonism.

Original languageEnglish
Pages (from-to)54-61
Number of pages8
JournalRegulatory Peptides
Volume148
Issue number1-3
DOIs
Publication statusPublished - Jun 5 2008

Fingerprint

Rats
Brain
Peptides
Immune Sera
Opioid Receptors
Opioid Analgesics
tyrosyl-proline
High Pressure Liquid Chromatography
Endorphins
Dynorphins
Vas Deferens
endomorphin 2
Dipeptides
Enkephalins
Biosynthetic Pathways
Assays
Rabbits
Weights and Measures
Antibodies

Keywords

  • [Gly]-endomorphins
  • Bioassays
  • Endomorphin
  • Novel endomorphin-2-immunoreactive species
  • Radioimmunoassay
  • Rat brain

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Physiology
  • Neuroscience(all)

Cite this

Detection of a novel immunoreactive endomorphin 2-like peptide in rat brain extracts. / Szemenyei, Erzsébet; Barna, I.; Mergl, Z.; Keresztes, Attila; Darula, Z.; Kató, Erzsébet; Tóth, Géza; Rónai, A.

In: Regulatory Peptides, Vol. 148, No. 1-3, 05.06.2008, p. 54-61.

Research output: Contribution to journalArticle

Szemenyei, Erzsébet ; Barna, I. ; Mergl, Z. ; Keresztes, Attila ; Darula, Z. ; Kató, Erzsébet ; Tóth, Géza ; Rónai, A. / Detection of a novel immunoreactive endomorphin 2-like peptide in rat brain extracts. In: Regulatory Peptides. 2008 ; Vol. 148, No. 1-3. pp. 54-61.
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