Parallel stimulations of in vitro and in situ [35S]GTPgammaS binding by endomorphin 1 and DAMGO in mouse brains

Peptides. 1998;19(4):755-8. doi: 10.1016/s0196-9781(97)00482-8.


Metabotropic activities of endomorphin 1, a candidate for endogenous mu-opioid receptor ligands, were examined in comparison with the actions of [D-Ala2, N-Me-Phe4, Gly5ol]-enkephalin/DAMGO, a well-known synthetic mu-opioid agonist. Endomorphin 1 stimulated [35S]GTPgammaS binding to synaptic membranes from the mouse amygdala in a naloxone-reversible manner. DAMGO had the same effect in such preparations. In in situ [35S]GTP-gammaS binding experiments using brain sections, both endomorphin 1 and DAMGO similarly stimulated this binding in specific cellular locations throughout the brain regions. These findings strongly support the view that endomorphin 1 selectively acts on a mu-opioid receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amygdala / metabolism
  • Animals
  • Autoradiography
  • Brain / drug effects*
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Enkephalins / pharmacology*
  • GTP-Binding Proteins / metabolism
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Ligands
  • Male
  • Mice
  • Oligopeptides / pharmacology*
  • Receptors, Opioid, mu / agonists*
  • Synaptic Membranes / metabolism


  • Enkephalins
  • Ligands
  • Oligopeptides
  • Receptors, Opioid, mu
  • endomorphin 1
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • GTP-Binding Proteins