What are the mechanisms of action and pharmacokinetics of calcium channel blockers?

Updated: Jan 28, 2020
  • Author: Juan G Ochoa, MD; Chief Editor: Selim R Benbadis, MD  more...
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Answer

Answer

Calcium channels exist in 3 known forms in the human brain: L, N, and T. These channels are small and are inactivated quickly. The influx of calcium currents in the resting state produces a partial depolarization of the membrane, facilitating the development of an action potential after rapid depolarization of the cell.

Calcium channels function as the " pacemakers " of normal rhythmic brain activity. This is particularly true of the thalamus. T-calcium channels have been known to play a role in the 3 per second spike-and-wave discharges of absence seizures. AEDs that inhibit these T-calcium channels are particularly useful for controlling absence seizures (see the image below).

Low-voltage calcium (Ca2+) currents (T-type) are r Low-voltage calcium (Ca2+) currents (T-type) are responsible for rhythmic thalamocortical spike and wave patterns of generalized absence seizures. Some antiepileptic drugs lock these channels, inhibiting underlying slow depolarizations necessary to generate spike-wave bursts.

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