[Cognitive Function and Calcium. Cognitive improvement through T type calcium channel stimulation]

Low-threshold Ca2+ spikes are mediated by T-type Ca2+ channels, which have fast inactivation and slow deactivation kinetics (transient) , and single channel conductance. The activation are triggered by -60 to -65 mV. T-type Ca2+ channels are predominantly expressed in the brain and heart pacemaker cells. Three subtypes of T-type Ca2+ channels Cav3.1 (α1G), Cav3.2 (α1H), Cav3.3 (α1I) encoding by CACNA1G, CACNA1H, CACNA1I genes have been cloned. Although high-threshold voltage-gated Ca2+ channels have auxiliary α2δ, β, γ subunits, T-type Ca2+ channels are composed only by α1 subunit. Although T-type Ca2+ channels are involved in the pace making in heart and a robust low-threshold Ca2+ spike in neurons, the physiological functions in the memory and synaptic plasticity remain unclear. In this paper, I would like to focus on the pathophysiological relevance of T-type Ca2+ channels in the brain functions including cognition.