28
Apr
T Type Calcium Channel Absence Epilepsy. T-type calcium channels are believed to play a critical role in the generation of the hypersynchronous oscillatory thalamocortical activity that underlies absence seizures and of the intrinsic burst firing of hippocampal pyramidal neurons in TLE. T-type calcium channels play a key role in this circuit. We carried out direct sequencing of exons 1-37 and the exon-intron boundaries of the alpha 1G gene in 48 Han Chinese patients with CAE and 48 normal controls. The most direct demonstration for the role of T-type channels and burst firing among TRN neurons in the generation of absence seizures can be provided by selective.
The function of T-type channels in TRN neurons in the genesis of absence epilepsy can be elucidated through the analysis of Ca V 32 and Ca V 33 T-type Ca 2 channels which are expressed in TRN neurons but not in TC neurons. Childhood absence epilepsy CAE a subtype of idiopathic generalized epilepsy IGE is characterized by bihemispheric 3Hz spikeandwave discharges SWDs that are known to involve Ttype calcium channels expressed in the thalamocortical network 1. Ttype calcium channels in seizures and epileptogenesis. It is well established that idiopathic generalized epilepsies IGEs show a polygenic origin and may arise from dysfunction of various types of voltage- and ligand-gated ion channels. T-type calcium channel blockers that attenuate thalamic burst firing and suppress absence seizures. Several lines of evidence have implicated the Ca V.
The ability of the T-type calcium channel antagonists to inhibit absence seizures and reduce the duration and cycle frequency of spike-and-wave discharges also suggests that T-current generated by T-type calcium channels is a key component in the formation of absence seizures.
Ttype calcium channels are believed to play a critical role in the generation of the hypersynchronous oscillatory thalamocortical activity that underlies absence seizures 37-39 and of the intrinsic burst firing of hippocampal pyramidal neurons in TLE 40-42. It is well established that idiopathic generalized epilepsies IGEs show a polygenic origin and may arise from dysfunction of various types of voltage- and ligand-gated ion channels. T-type calcium channels and burst-firing in absence epilepsy Further evidence implicating burst-firing in seizures is observed in rodents with either genetically-induced or spontaneously-acquired epileptic phenotypes 41 50. Low voltage-activated T-type calcium channels underlie the burst-firing associated with spike-and-wave discharges observed on electroencephalography recordings during certain forms of epileptic seizures. T-type calcium channels have been implicated to play a role in the modulation of anxiety as Cav32 deficient mice display an elevated anxiety-like phenotype in a lightdark conflict test EPM and open field test. The three T-type calcium channels Ca v 31 Ca v 32 and Ca v 33 are widely but differentially expressed in the thalamocortical circuitry implicated in absence seizures.