Opioid receptor independent inhibition of Ca2+ and K+ currents in NG108-15 cells by the kappa opioid receptor agonist U50488H

Neuroreport. 1996 Jul 29;7(11):1809-12. doi: 10.1097/00001756-199607290-00024.


The whole-cell patch clamp technique was used to investigate the actions of the opioid agonist U50488H on Ca2+ and K+ currents in differentiated NG108-15 cells. U50488H (5-50 microM) caused a concentration-dependent, reversible inhibition of high voltage-activated Ca2+ currents which persisted in the presence of nifedipine (2 microM), indicating a blockade of N-type Ca2+ channels. The actions of U50488H were also observed in the presence of 30 microM naloxone, which fully abolished current inhibition caused by a selective delta opioid receptor agonist. U50488H also inhibited Ca(2+)-insensitive, voltage-gated K+ currents in NG108-15 cells in the presence of naloxone. Our results indicate that U50488H can inhibit neuronal ionic channels via a mechanism which does not involve activation of kappa opioid receptors.

MeSH terms

  • 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer
  • Animals
  • Calcium Channels / drug effects*
  • Cells, Cultured / drug effects
  • Dose-Response Relationship, Drug
  • Hybrid Cells / drug effects*
  • Patch-Clamp Techniques
  • Potassium Channels / drug effects*
  • Pyrrolidines / pharmacology*
  • Receptors, Opioid, kappa / agonists*


  • Calcium Channels
  • Potassium Channels
  • Pyrrolidines
  • Receptors, Opioid, kappa
  • 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer