Protein kinase C epsilon mediates up-regulation of N-type calcium channels by ethanol

Mol Pharmacol. 2000 Jan;57(1):53-8.

Abstract

Brief exposure to ethanol inhibits L-type and N-type voltage-gated calcium channels in neural cells. Although chronic ethanol exposure up-regulates the density and function of L-type channels via a protein kinase C (PKC) delta-dependent mechanism, the effect of prolonged ethanol exposure on N-type channels is not known. Using PC12 cells, we found that exposure to 25 to 150 mM ethanol for 0 to 8 days produced a time- and concentration-dependent increase in the density of binding sites for the N-type channel antagonist (125)I-omega-conotoxin GVIA. This was associated with an increase in omega-conotoxin GVIA-sensitive, depolarization-evoked rises in [Ca(2+)](i). Increases in (125)I-omega-conotoxin GVIA binding also were observed in the frontal cortex and the hippocampus, but not in the thalamus of mice exposed to ethanol vapor for 3 days. In PC12 cells, increases in (125)I-omega-conotoxin GVIA binding were blocked by the PKC inhibitor bisindolylmaleimide I and by expression of a selective peptide inhibitor of PKCepsilon. Expression of a selective inhibitor of PKCdelta did not alter ethanol-induced increases in (125)I-omega-conotoxin GVIA binding. These findings indicate that PKCepsilon mediates up-regulation of N-type channels by ethanol. Because N-type channels modulate calcium-dependent neurotransmitter release, these findings suggest a mechanism that may contribute to neuronal hyperexcitability observed during alcohol withdrawal.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • Brain / drug effects
  • Brain / metabolism
  • Calcium / metabolism
  • Calcium Channel Blockers / metabolism
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels, N-Type / drug effects
  • Calcium Channels, N-Type / metabolism*
  • Ethanol / pharmacology*
  • Iodine Radioisotopes
  • Isoenzymes / metabolism*
  • Male
  • Mice
  • PC12 Cells
  • Protein Kinase C / metabolism*
  • Protein Kinase C-epsilon
  • Rats
  • Up-Regulation
  • omega-Conotoxin GVIA / metabolism
  • omega-Conotoxin GVIA / pharmacology

Substances

  • Calcium Channel Blockers
  • Calcium Channels, N-Type
  • Iodine Radioisotopes
  • Isoenzymes
  • Ethanol
  • omega-Conotoxin GVIA
  • Prkce protein, mouse
  • Prkce protein, rat
  • Protein Kinase C
  • Protein Kinase C-epsilon
  • Calcium