T-type Ca2+ channels in absence epilepsy

Pflugers Arch. 2014 Apr;466(4):719-34. doi: 10.1007/s00424-014-1461-y. Epub 2014 Feb 13.

Abstract

Absence epilepsy accompanies the paroxysmal oscillations in the thalamocortical circuit referred as spike and wave discharges (SWDs). Low-threshold burst firing mediated by T-type Ca(2+) channels highly expressed in both inhibitory thalamic reticular nuclei (TRN) and excitatory thalamocortical (TC) neurons has been correlated with the generation of SWDs. A generally accepted view has been that rhythmic burst firing mediated by T-type channels in both TRN and TC neurons are equally critical in the generation of thalamocortical oscillations during sleep rhythms and SWDs. This review examined recent studies on the T-type channels in absence epilepsy which leads to an idea that even though both TRN and TC nuclei are required for thalamocortical oscillations, the contributions of T-type channels to TRN and TC neurons are not equal in the genesis of sleep spindles and SWDs. Accumulating evidence revealed a crucial role of TC T-type channels in SWD generation. However, the role of TRN T-type channels in SWD generation remains controversial. Therefore, a deeper understanding of the functional consequences of modulating each T-type channel subtype could guide the development of therapeutic tools for absence seizures while minimizing side effects on physiological thalamocortical oscillations.

Publication types

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

MeSH terms

  • Action Potentials / physiology*
  • Animals
  • Calcium Channels, T-Type / physiology*
  • Electroencephalography / trends
  • Epilepsy, Absence / diagnosis
  • Epilepsy, Absence / genetics
  • Epilepsy, Absence / physiopathology*
  • Humans
  • Mutation / physiology
  • Thalamus / physiopathology*

Substances

  • Calcium Channels, T-Type