Inhibition of N-type calcium currents by lamotrigine in rat amygdalar neurones.
Lamotrigine (LAG) is a new anticonvulsant drug for the treatment of partial and secondarily generalized seizures. The present study was aimed at elucidating the possible involvement of Ca2+ channels in the action of LAG using whole-cell patch clamp recordings in acutely dissociated amygdalar neurones. Whole-cell Ca2+ currents (ICa) were elicited by 200 ms step commands from -70 mV to -10 mV. Application of LAG reduced the ICa by an average of 40.3 +/- 3.2%. The inhibition of ICa by LAG was markedly reduced or eliminated in the presence of the N-type Ca2+ channel blocker omega-conotoxin-GVIA (1 microM). These results suggest that LAG may exert its anticonvulsant effect through inhibition of presynaptic N-type Ca2+ channels, thereby reducing glutamate release.
Wang
S J
SJ
Department of Pharmacology, National Cheng-Kung University, Tainan City, Taiwan.
Huang
C C
CC
Hsu
K S
KS
Tsai
J J
JJ
Gean
P W
PW
D000679:Amygdala / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D004594:Electrophysiology; D066298:In Vitro Techniques; D000077213:Lamotrigine; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014227:Triazines / Q000494:pharmacology*; D020866:omega-Conotoxin GVIA
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010455:Peptides; D014227:Triazines; D020866:omega-Conotoxin GVIA; D000077213:Lamotrigine