Mu-opioid-receptor-mediated inhibition of the N-type calcium-channel current

Proc Biol Sci. 1991 May 22;244(1310):129-35. doi: 10.1098/rspb.1991.0061.


The predominant consequences of mu-opioid-receptor activation are depression of both neuronal activity and transmitter release. Mu-Opioid agonists have previously been observed to increase a potassium conductance and to inhibit adenylate cyclase. We now report that activation of mu-opioid receptors directly decreases the N-type calcium-channel current in a differentiated, human neuroblastoma cell line (SH-SY5Y). The coupling between the mu-opioid receptor and the calcium channel involves a pertussis toxin-sensitive G protein and is independent of changes in adenylate cyclase activity. The inhibition of the calcium-channel current is voltage dependent because it is largely overcome by strong membrane depolarization. It is not associated with changes in the kinetics of current inactivation. Therefore, the mu-receptor belongs to the superfamily of G-protein-coupled, inhibitory neurotransmitter receptors which modulate the activity of calcium and potassium channels and adenylate cyclase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylate Cyclase Toxin
  • Adenylyl Cyclase Inhibitors
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism*
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Enkephalins / pharmacology
  • GTP-Binding Proteins / metabolism
  • Humans
  • Membrane Potentials
  • Naloxone / pharmacology
  • Pertussis Toxin
  • Receptors, Opioid / drug effects
  • Receptors, Opioid / metabolism*
  • Receptors, Opioid, mu
  • Tumor Cells, Cultured / drug effects
  • Tumor Cells, Cultured / metabolism
  • Virulence Factors, Bordetella / pharmacology


  • Adenylate Cyclase Toxin
  • Adenylyl Cyclase Inhibitors
  • Calcium Channels
  • Enkephalins
  • Receptors, Opioid
  • Receptors, Opioid, mu
  • Virulence Factors, Bordetella
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Naloxone
  • Pertussis Toxin
  • GTP-Binding Proteins