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 Ca2+ 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.
Bibliographical noteFunding Information:
We thank our current and former colleagues for their contributions to what was discussed in this article. This work was supported by the fund from Institute for Basic Science(HQ1301), and Translational Research Center for Protein Function Control (2009-0083522) and Basic Science Research Program (2012-0004313) and Pioneer Research Center Program (2012-0001087), funded by the Ministry of Education, Science and Technology in Korea.
All Science Journal Classification (ASJC) codes
- Clinical Biochemistry
- Physiology (medical)