What question did this study set out to answer?

Investigate the potential- and frequency-dependent inhibitory effects of phenytoin and carbamazepine on ionic membrane currents in mammalian myelinated nerve fibers.

June 1, 1989Epilepsia

Phenytoin and Carbamazepine: Potential‐ and Frequency‐Dependent Block of Na Currents in Mammalian Myelinated Nerve Fibers

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Investigate the potential- and frequency-dependent inhibitory effects of phenytoin and carbamazepine on ionic membrane currents in mammalian myelinated nerve fibers.
Conducted voltage clamp experiments on isolated single myelinated nerve fibers of rats.
Evaluated concentration-dependent modifications of sodium channel gating kinetics, steady-state inactivation, and recovery rates across varying membrane potentials and stimulation frequencies.
Phenytoin and carbamazepine acted as selective blockers of sodium channels via a potential-dependent block reversed by hyperpolarization, with phenytoin demonstrating a dissociation constant (Kd) of 37 µM.
Both agents produced equimolar, concentration-dependent shifts of the steady-state sodium inactivation curve toward more negative membrane potentials and reduced its slope.
Both drugs delayed recovery from sodium channel inactivation, with phenytoin exerting a more pronounced slowing effect and frequency-dependent block than carbamazepine.

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Implication

Electrophysiological study demonstrates potential- and frequency-dependent sodium channel blockade by phenytoin and carbamazepine in rat nerve fibers, indicating a modulated receptor mechanism.

Cite This Study

Schwarz et al. (1989) studied this question.

synapsesocial.com/papers/6a887563dea5055e4b609a7e https://doi.org/10.1111/j.1528-1157.1989.tb05300.x

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Implication

Electrophysiological study demonstrates potential- and frequency-dependent sodium channel blockade by phenytoin and carbamazepine in rat nerve fibers, indicating a modulated receptor mechanism.

Phenytoin and Carbamazepine: Potential‐ and Frequency‐Dependent Block of Na Currents in Mammalian Myelinated Nerve Fibers

Key Points

Discussion

Implication

Cite This Study

Phenytoin and Carbamazepine: Potential‐ and Frequency‐Dependent Block of Na Currents in Mammalian Myelinated Nerve Fibers

Key Points

Discussion

Implication

Cite This Study

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