Methadone but not morphine inhibits lubiprostone-stimulated Cl- currents in T84 intestinal cells and recombinant human ClC-2, but not CFTR Cl- currents

Cell Biochem Biophys. 2013 May;66(1):53-63. doi: 10.1007/s12013-012-9406-6.


In clinical trials, methadone, but not morphine, appeared to prevent beneficial effects of lubiprostone, a ClC-2 Cl(-) channel activator, on opioid-induced constipation. Effects of methadone and morphine on lubiprostone-stimulated Cl(-) currents were measured by short circuit current (Isc) across T84 cells. Whole cell patch clamp of human ClC-2 (hClC-2) stably expressed in HEK293 cells and in a high expression cell line (HEK293EBNA) as well as human CFTR (hCFTR) stably expressed in HEK293 cells was used to study methadone and morphine effects on recombinant hClC-2 and hCFTR Cl(-) currents. Methadone but not morphine inhibited lubiprostone-stimulated Isc in T84 cells with half-maximal inhibition at 100 nM. Naloxone did not affect lubiprostone stimulation or methadone inhibition of Isc. Lubiprostone-stimulated Cl(-) currents in hClC-2/HEK293 cells, but not forskolin/IBMX-stimulated Cl(-) currents in hCFTR/HEK293 cells, were inhibited by methadone, but not morphine. HEK293EBNA cells expressing hClC-2 showed time-dependent, voltage-activated, CdCl2-inhibited Cl(-) currents in the absence (control) and the presence of lubiprostone. Methadone, but not morphine, inhibited control and lubiprostone-stimulated hClC-2 Cl(-) currents with half-maximal inhibition at 100 and 200-230 nM, respectively. Forskolin/IBMX-stimulated hClC-2 Cl(-) currents were also inhibited by methadone. Myristoylated protein kinase inhibitor (a specific PKA inhibitor) inhibited forskolin/IBMX- but not lubiprostone-stimulated hClC-2 Cl(-) currents. Methadone caused greater inhibition of lubiprostone-stimulated currents added before patching (66.1 %) compared with after patching (28.7 %). Methadone caused inhibition of lubiprostone-stimulated Cl(-) currents in T84 cells and control; lubiprostone- and forskolin/IBMX-stimulated recombinant hClC-2 Cl(-) currents may be the basis for reduced efficacy of lubiprostone in methadone-treated patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alprostadil / analogs & derivatives*
  • Alprostadil / pharmacology
  • Biological Transport
  • Cadmium Chloride / pharmacology
  • Chloride Channels / antagonists & inhibitors
  • Chloride Channels / drug effects*
  • Colforsin / pharmacology
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Drug Evaluation, Preclinical
  • HEK293 Cells
  • Humans
  • Lubiprostone
  • Methadone / pharmacology*
  • Morphine / pharmacology*
  • Naloxone / pharmacology
  • Patch-Clamp Techniques
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Time Factors
  • Transfection


  • CFTR protein, human
  • Chloride Channels
  • Recombinant Proteins
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Colforsin
  • Naloxone
  • Lubiprostone
  • Morphine
  • Alprostadil
  • Cadmium Chloride
  • Methadone