In vitro binding and signaling profile of the novel μ opioid receptor agonist endomorphin 2 in rat brain membranes

Mariana Spetea, Krisztina Monory, Csaba Tömböly, Géza Tóth, Eleni Tzavara, Sándor Benyhe, Jacques Hanoune, Anna Borsodi

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

The recently discovered endogenous μ receptor selective endomorphin 2 was prepared in tritiated form by a catalytic dehalogenation method resulting in a specific radioactivity of 1.98 TBq/mmol (53.4 Ci/mmol), and used for in vitro labelling of rat brain membranes. The binding was saturable, stereospecific and of high affinity (K(d): 0.97 and 1.12 nM based on kinetic and equilibrium binding studies, respectively). The maximal number of binding sites (B(max)) was found to be 114.8 fmol/mg protein. [3H]Endomorphin 2 was displaced by μ-receptor selective specific peptides and heterocyclic compounds with high affinity, whereas κ and δ receptor specific ligands were much less potent. The K(i) values of endomorphin 1 and 2 in inhibiting [3H]naloxone binding increased by 15-fold in the presence of 100 mM NaCl which indicates the agonist property of these peptides. Endomorphins stimulated [35S]GTPγS binding and inhibited adenylyl cyclase activity which also provides evidence for the agonist character of endomorphins.

Original languageEnglish
Pages (from-to)720-725
Number of pages6
JournalBiochemical and biophysical research communications
Volume250
Issue number3
DOIs
Publication statusPublished - Sep 29 1998

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'In vitro binding and signaling profile of the novel μ opioid receptor agonist endomorphin 2 in rat brain membranes'. Together they form a unique fingerprint.

  • Cite this