Molecular and functional characterization of a family of rat brain T-type calcium channels
| Autor: | Anthony Stea, David L. Baillie, Terrance P. Snutch, Kevin S. Hamming, Janette Mezeyova, John E. McRory, Kathy G. Sutton, Celia M. Santi |
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| Rok vydání: | 2000 |
| Předmět: |
DNA
Complementary Molecular Sequence Data chemistry.chemical_element Biology Calcium Biochemistry Permeability Cell Line Calcium Channels T-Type Animals Humans Northern blot Amino Acid Sequence RNA Messenger Cloning Molecular Molecular Biology Expressed Sequence Tags Voltage-dependent calcium channel Base Sequence Sequence Homology Amino Acid Calcium channel HEK 293 cells T-type calcium channel Brain Cell Biology Rats R-type calcium channel Electrophysiology Alternative Splicing Kinetics chemistry Barium Biophysics Ion Channel Gating |
| Zdroj: | The Journal of biological chemistry. 276(6) |
| ISSN: | 0021-9258 |
| Popis: | Voltage-gated calcium channels represent a heterogenous family of calcium-selective channels that can be distinguished by their molecular, electrophysiological, and pharmacological characteristics. We report here the molecular cloning and functional expression of three members of the low voltage-activated calcium channel family from rat brain (alpha(1G), alpha(1H), and alpha(1I)). Northern blot and reverse transcriptase-polymerase chain reaction analyses show alpha(1G), alpha(1H), and alpha(1I) to be expressed throughout the newborn and juvenile rat brain. In contrast, while alpha(1G) and alpha(1H) mRNA are expressed in all regions in adult rat brain, alpha(1I) mRNA expression is restricted to the striatum. Expression of alpha(1G), alpha(1H), and alpha(1I) subunits in HEK293 cells resulted in calcium currents with typical T-type channel characteristics: low voltage activation, negative steady-state inactivation, strongly voltage-dependent activation and inactivation, and slow deactivation. In addition, the direct electrophysiological comparison of alpha(1G), alpha(1H), and alpha(1I) under identical recording conditions also identified unique characteristics including activation and inactivation kinetics and permeability to divalent cations. Simulation of alpha(1G), alpha(1H), and alpha(1I) T-type channels in a thalamic neuron model cell produced unique firing patterns (burst versus tonic) typical of different brain nuclei and suggests that the three channel types make distinct contributions to neuronal physiology. |
| Databáze: | OpenAIRE |
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