T-type calcium channels mediate the transition between tonic and phasic firing in thalamic neurons.
AUTOR(ES)
Suzuki, S
RESUMO
Thalamic neurons undergo a shift from tonic to phasic (burst) firing upon hyperpolarization. This state transition results from deinactivation of a regenerative depolarizing event referred to as the low-threshold spike. Isolated adult guinea pig thalamic (dorsal lateral geniculate) neurons exhibited low-threshold spikes that could be blocked by low concentrations of nickel but were unaffected by the dihydropyridine nimodipine. Whole-cell voltage-clamp recordings from these cells demonstrated a low-threshold, rapidly inactivating (T) Ca2+ current that manifested similar voltage dependency and time course as the low-threshold spike. Like low-threshold spikes, the T-type Ca2+ current was eliminated by nickel but was unaffected by nimodipine. In thalamic neurons, T-type Ca2+ channels underlie the low-threshold spike and, therefore, play a critical role in regulating the firing pattern of these cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=298030Documentos Relacionados
- Direct inhibition of T-type calcium channels by the endogenous cannabinoid anandamide
- Block of Thalamic T-Type Ca2+ Channels by Ethosuximide Is Not the Whole Story
- T-type calcium channels are regulated by hypoxia/reoxygenation in ventricular myocytes
- Phenotype-specific expression of T-type calcium channels in neurons of the major pelvic ganglion of the adult male rat.
- T-type calcium channels in adrenal glomerulosa cells: GTP-dependent modulation by angiotensin II.
