The rat brain calcium channel alpha 1 subunit (rbE-II) transiently activated at negative membrane potentials, required strong hyperpolarization to deinactivate, and was highly sensitive to nickel block.
The cloning and characterization of the rbE-II calcium channel subunit reveals it functions as a low voltage-activated calcium channel that may modulate neuronal firing patterns.
Oscillatory firing patterns are an intrinsic property of some neurons and have an important function in information processing. In some cells, low voltage-activated calcium channels have been proposed to underlie a depolarizing potential that regulates bursting. The sequence of a rat brain calcium channel alpha 1 subunit (rbE-II) was deduced. Although it is structurally related to high voltage-activated calcium channels, the rbE-II channel transiently activated at negative membrane potentials, required a strong hyperpolarization to deinactivate, and was highly sensitive to block by nickel. In situ hybridization showed that rbE-II messenger RNA is expressed in regions throughout the central nervous system. The electrophysiological properties of the rbE-II current are consistent with a type of low voltage-activated calcium channel that requires membrane hyperpolarization for maximal activity, which suggests that rbE-II may be involved in the modulation of firing patterns.
Soong et al. (1993) studied this question. rbE-II calcium channel alpha 1 subunit was evaluated on Electrophysiological properties and expression of rbE-II. The rat brain calcium channel alpha 1 subunit (rbE-II) transiently activated at negative membrane potentials, required strong hyperpolarization to deinactivate, and was highly sensitive to nickel block.