T-type calcium channel in mammalian CNS neurones.
1. In all neurones freshly isolated from various brain regions of newborn, adult and aged rats, the T-type Ca2+ currents were elicited by step depolarizations to potentials more positive than -60 mV from a holding potential of -100 mV, and reached a peak in the current-voltage relationship around -30 mV. 2. The activation and inactivation processes were highly potential-dependent, and the latter was fitted by a single exponential function. 3. It was concluded that mammalian brain neurones possess a definite class of T-type Ca2+ channel characterized by both current kinetics and ion selectivity for Ca2+, Ba2+ and Sr2+. However, the pharmacological nature of the T-type Ca2+ channel differed from that in other tissues such as cardiac and smooth muscle cells, peripheral neurones, and cultured cells.
Akaike
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Department of Neurophysiology, Tohoku University School of Medicine, Sendai, Japan.
D000818:Animals; D001921:Brain / Q000166:cytology*; D015220:Calcium Channels / Q000502:physiology*; D002413:Cations, Divalent; D004594:Electrophysiology; D007700:Kinetics; D009474:Neurons / Q000502:physiology*
D015220:Calcium Channels; D002413:Cations, Divalent