The conduction block produced by oxcarbazepine in the isolated rat sciatic nerve: a comparison with lamotrigine.
OBJECTIVE
Oxcarbazepine is an antiepileptic drug widely used for the treatment of neuropathic pain. In the present study, the effects of oxcarbazepine and lamotrigine on conduction properties in the rat sciatic nerves were examined.


METHODS
The experiments were conducted with in vitro sucrose-gap technique on the isolated wistar rat sciatic nerves. The compound action potentials were obtained by tonic (single) and phasic (10, 40, and 100 Hz) stimulation.


RESULTS
Oxcarbazepine produced a significant concentration- and frequency-dependent reduction in the compound action potential amplitude. When the two drugs were applied at concentrations that produced equal levels of tonic (i.e., non-frequency-dependent) conduction block, oxcarbazepine produced the greatest phasic (i.e., frequency-dependent) conduction block, followed by lamotrigine. Oxcarbazepine and lamotrigine reduced the 4-aminopyridine-induced amplitude of delayed depolarization; however, oxcarbazepine had a significantly greater effect than lamotrigine.


CONCLUSIONS
These results suggest that oxcarbazepine produces more potent frequency-dependent conduction block than lamotrigine, and suppresses the delayed depolarization which contributes to sensory signaling and may play a role in neuropathic pain. The findings provide insight into the mechanisms of action of oxcarbazepine and lamotrigine and may help in the development of novel therapies for neuropathic pain.
Guven
Mustafa
M
Department of Biophysics, School of Medicine, University of Cukurova, 01330 Adana, Turkey.
Kahraman
Ibrahim
I
Koc
Filiz
F
Bozdemir
Hacer
H
Sarica
Yakup
Y
Gunay
Ismail
I
D015761:4-Aminopyridine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D002220:Carbamazepine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D000077213:Lamotrigine; D009431:Neural Conduction / Q000187:drug effects* / Q000502:physiology; D000078330:Oxcarbazepine; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000187:drug effects* / Q000502:physiology; D014227:Triazines / Q000494:pharmacology*
D000927:Anticonvulsants; D014227:Triazines; D002220:Carbamazepine; D015761:4-Aminopyridine; D000077213:Lamotrigine; D000078330:Oxcarbazepine