Opiorphin highly improves the specific binding and affinity of MERF and MEGY to rat brain opioid receptors

Fanni Tóth, Géza Tóth, S. Benyhe, Catherine Rougeot, Mária Wollemann

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Endogenously occurring opioid peptides are rapidly metabolized by different ectopeptidases. Human opiorphin is a recently discovered natural inhibitor of the enkephalin-inactivating neutral endopeptidase (NEP) and aminopeptidase-N (AP-N) (Wisner et al., 2006). To date, in vitro receptor binding experiments must be performed either in the presence of a mixture of peptidase inhibitors and/or at low temperatures, to block peptidase activity. Here we demonstrate that, compared to classic inhibitor cocktails, opiorphin dramatically increases the binding of [3H]MERF and [3H]MEGY ligands to rat brain membrane preparations. We found that at 0°C the increase in specific binding is as high as 40-60% and at 24°C this rise was even higher. In contrast, the binding of the control [3H]endomorphin-1, which is relatively slowly degraded in rat brain membrane preparations, was not enhanced by opiorphin compared to other inhibitors. In addition, in homologous binding displacement experiments, the IC50 affinity values measured at 24°C were also significantly improved using opiorphin compared to the inhibitor cocktail. In heterologous binding experiments the differences were less obvious, but still pronounced using [3H]MERF and MEGY compared to dynorphin1-11, or naloxone and DAGO competitor ligands.

Original languageEnglish
Pages (from-to)71-75
Number of pages5
JournalRegulatory Peptides
Volume178
Issue number1-3
DOIs
Publication statusPublished - Oct 10 2012

Fingerprint

glutaminyl-arginyl-phenylalanyl-seryl-arginine
Opioid Receptors
Rats
Brain
Ala(2)-MePhe(4)-Gly(5)-enkephalin
Ligands
Membranes
CD13 Antigens
Neprilysin
Opioid Peptides
Enkephalins
Experiments
Naloxone
Protease Inhibitors
Inhibitory Concentration 50
Peptide Hydrolases
Temperature

Keywords

  • Endomorphin-1
  • Met-enkephalin-Arg-Phe
  • Met-enkephalin-Gly-Tyr
  • Naloxone
  • Opiorphin
  • Peptidase inhibitors

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Endocrinology
  • Physiology
  • Cellular and Molecular Neuroscience

Cite this

Opiorphin highly improves the specific binding and affinity of MERF and MEGY to rat brain opioid receptors. / Tóth, Fanni; Tóth, Géza; Benyhe, S.; Rougeot, Catherine; Wollemann, Mária.

In: Regulatory Peptides, Vol. 178, No. 1-3, 10.10.2012, p. 71-75.

Research output: Contribution to journalArticle

Tóth, Fanni ; Tóth, Géza ; Benyhe, S. ; Rougeot, Catherine ; Wollemann, Mária. / Opiorphin highly improves the specific binding and affinity of MERF and MEGY to rat brain opioid receptors. In: Regulatory Peptides. 2012 ; Vol. 178, No. 1-3. pp. 71-75.
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