Guanine nucleotide regulation of [125I]beta-endorphin binding to NG108-15 and SK-N-SH cell membranes: specific cation requirements

Brain Res. 1989 Jul 24;493(1):23-32. doi: 10.1016/0006-8993(89)90996-7.


Regulation of [125I]beta h-endorphin binding by guanine nucleotides was investigated in membrane preparations from two opioid receptor-containing cell lines: NG108-15, which contains only delta opioid receptors, and SK-N-SH, which contains predominantly mu opioid receptors. In contrast to the binding of the delta-selective agonist [3H][D-penicillamine2,D-penicillamine5]enkephalin to NG108-15 cell membranes, and of the mu-selective agonist [3H][D-Ala2,MePhe4,Gly-ol5]enkephalin to SK-N-SH cell membranes, [125I]beta h-endorphin binding to NG108-15 and SK-N-SH cell membranes was not altered by guanosine triphosphate (GTP) or guanylyl-5'-imidodiphosphate (Gpp(NH)p) in the absence of cations. However, in the presence of NaCl, [125I]beta h-endorphin binding to both cell lines was inhibited by GTP and Gpp(NH)p in a concentration-dependent manner. In SK-N-SH cell membranes, the ability of sodium to promote regulation of [125I]beta h-endorphin binding by GTP was mimicked by the monovalent cations lithium and potassium, but not by the divalent cations magnesium, calcium, or manganese. In NG108-15 cell membranes, only sodium was effective in promoting inhibition of [125I]beta h-endorphin binding by GTP. The effect of GTP or Gpp(NH)p in the presence of sodium was also observed with guanosine diphosphate, but not guanosine monophosphate or any of the non-guanine nucleotides tested. These results indicate that the presence of monovalent cations is required for regulation of [125I]beta h-endorphin binding by guanine nucleotides, and that the specificity of this cation requirement differs between the mu and delta receptor-containing cell lines.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cations
  • Cell Membrane / metabolism
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Enkephalin, D-Penicillamine (2,5)-
  • Enkephalin, Leucine* / analogs & derivatives*
  • Enkephalins / metabolism
  • Glioma
  • Guanine Nucleotides / pharmacology*
  • Guanosine Diphosphate / pharmacology
  • Guanosine Triphosphate / pharmacology
  • Guanylyl Imidodiphosphate / pharmacology
  • Humans
  • Hybrid Cells
  • Neuroblastoma
  • Oligopeptides / metabolism
  • Receptors, Opioid / drug effects
  • Receptors, Opioid / metabolism*
  • Receptors, Opioid, delta
  • Receptors, Opioid, mu
  • Sodium Chloride / pharmacology
  • Tumor Cells, Cultured
  • beta-Endorphin / metabolism*


  • Cations
  • Enkephalins
  • Guanine Nucleotides
  • Oligopeptides
  • Receptors, Opioid
  • Receptors, Opioid, delta
  • Receptors, Opioid, mu
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Guanosine Diphosphate
  • Guanylyl Imidodiphosphate
  • Sodium Chloride
  • Enkephalin, Leucine
  • beta-Endorphin
  • enkephalin, Ser(2), Leu(5), Thr(6)-
  • Guanosine Triphosphate
  • Enkephalin, D-Penicillamine (2,5)-