Eslicarbazepine and the enhancement of slow inactivation of voltage-gated sodium channels: a comparison with carbamazepine, oxcarbazepine and lacosamide.

Abstract

This study aimed at evaluating the effects of eslicarbazepine, carbamazepine (CBZ), oxcarbazepine (OXC) and lacosamide (LCM) on the fast and slow inactivated states of voltage-gated sodium channels (VGSC). The anti-epileptiform activity was evaluated in mouse isolated hippocampal slices. The anticonvulsant effects were evaluated in MES and the 6-Hz psychomotor tests. The whole-cell patch-clamp technique was used to investigate the effects of eslicarbazepine, CBZ, OXC and LCM on sodium channels endogenously expressed in N1E-115 mouse neuroblastoma cells. CBZ and eslicarbazepine exhibit similar concentration dependent suppression of epileptiform activity in hippocampal slices. In N1E-115 mouse neuroblastoma cells, at a concentration of 250 μM, the voltage dependence of the fast inactivation was not influenced by eslicarbazepine, whereas LCM, CBZ and OXC shifted the V0.5 value (mV) by -4.8, -12.0 and -16.6, respectively. Eslicarbazepine- and LCM-treated fast-inactivated channels recovered similarly to control conditions, whereas CBZ- and OXC-treated channels required longer pulses to recover. CBZ, eslicarbazepine and LCM shifted the voltage dependence of the slow inactivation (V0.5, mV) by -4.6, -31.2 and -53.3, respectively. For eslicarbazepine, LCM, CBZ and OXC, the affinity to the slow inactivated state was 5.9, 10.4, 1.7 and 1.8 times higher than to the channels in the resting state, respectively. In conclusion, eslicarbazepine did not share with CBZ and OXC the ability to alter fast inactivation of VGSC. Both eslicarbazepine and LCM reduce VGSC availability through enhancement of slow inactivation, but LCM demonstrated higher interaction with VGSC in the resting state and with fast inactivation gating.

• Authors: Simon Hebeisen, Nuno Pires, Ana I Loureiro, Maria João Bonifácio, Nuno Palma, Andrew Whyment, David Spanswick, Patrício Soares-da-Silva
• Journal: Neuropharmacology (Neuropharmacology) Vol. 89 Pg. 122-35 (Feb 2015) ISSN: 1873-7064 [Electronic] England
• PMID: 25242737 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical References

• Acetamides
• Anticonvulsants
• Dibenzazepines
• Voltage-Gated Sodium Channels
• Carbamazepine
• Lacosamide
• eslicarbazepine
• Oxcarbazepine

Topics

• Acetamides (pharmacology)
• Animals
• Anticonvulsants (pharmacology)
• Carbamazepine (analogs & derivatives, pharmacology)
• Cell Line, Tumor
• Dibenzazepines (pharmacology)
• Dose-Response Relationship, Drug
• Hippocampus (drug effects, physiology)
• Lacosamide
• Male
• Mice
• Organ Culture Techniques
• Oxcarbazepine
• Time Factors
• Voltage-Gated Sodium Channels (physiology)