Inhibition of T-type calcium channels protects neurons from delayed ischemia-induced damage

Mol Pharmacol. 2005 Jul;68(1):84-9. doi: 10.1124/mol.104.010066. Epub 2005 Apr 25.

Abstract

Intracellular calcium increase is an early key event triggering ischemic neuronal cell damage. The role of T-type voltage-gated calcium channels in the neuronal response to ischemia, however, has never been studied. Using an in vitro model of ischemia-induced delayed cell death in rat organotypic hippocampal slice cultures, we show that T-type calcium channels inhibitors drastically reduce ischemic cell damage. Immunostaining studies reveal the existence of Ca(V)3.1 and Ca(V)3.2 types of low-voltage-activated calcium channels in rat organotypic hippocampal cultures. Low extracellular calcium (100 nM) or increase of intracellular calcium buffering ability by BAPTA-acetoxymethyl ester significantly reduced ischemia-induced neuronal damage. Pharmacological inhibition of the T-type calcium current by mibefradil, kurtoxin, nickel, zinc, and pimozide during the oxygen-glucose deprivation episode provided a significant protection against delayed neuronal death. Mibefradil and nickel exerted neuroprotective effects, not only if administrated during the oxygen-glucose deprivation episode but also in conditions of postischemic treatment. These data point to a role of T-type calcium currents in ischemia-induced, calcium-mediated neuronal cell damage and suggest a possible new pharmacological approach to stroke treatment.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Ischemia / metabolism*
  • Brain Ischemia / pathology
  • Brain Ischemia / prevention & control*
  • Calcium Channel Blockers / pharmacology*
  • Calcium Channels, T-Type / metabolism*
  • Cell Death / drug effects
  • Cell Death / physiology
  • Cell Line
  • Hippocampus / cytology
  • Hippocampus / drug effects
  • Hippocampus / metabolism
  • Humans
  • Neurons / drug effects
  • Neurons / metabolism*
  • Neuroprotective Agents / pharmacology*
  • Organ Culture Techniques
  • Perfusion
  • Rats

Substances

  • Calcium Channel Blockers
  • Calcium Channels, T-Type
  • Neuroprotective Agents