Temporal lobe and petit mal antiepileptics differentially affect ventral lateral thalamic and motor cortex excitability patterns.
Evoked potential (EP) analysis of the somatomotor pathway in cats revealed that the temporal lobe anticonvulsant carbamazepine suppresses the thalamic relay, whereas the petit mal antiepileptic ethosuximide acts on the cortex. Moreover, a history of temporal lobe epilepsy (amygdala kindling) maximized thalamic response to carbamazepine, especially during sleep states vulnerable to generalized kindled seizures. Ethosuximide accentuated cortical response during sleep and awakening states vulnerable to generalized spike-wave complexes, regardless of a history of petit mal seizures (systemic penicillin epilepsy). The findings provide a neural basis for differential drug effects on generalized temporal lobe and petit mal epilepsy and further suggest that a chronic seizure disorder can create a predisposition for antiepileptic drug sensitivity.
Shouse
M N
MN
VA Medical Center, Sepulveda, CA 91343.
Stroh
P J
PJ
Vreeken
T
T
D000818:Animals; D002220:Carbamazepine / Q000494:pharmacology; D002415:Cats; D004195:Disease Models, Animal; D004832:Epilepsy, Absence / Q000503:physiopathology*; D005013:Ethosuximide / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D009044:Motor Cortex / Q000187:drug effects / Q000503:physiopathology*; D012016:Reference Values; D012890:Sleep / Q000187:drug effects / Q000502:physiology; D013702:Temporal Lobe / Q000187:drug effects / Q000503:physiopathology*; D013788:Thalamus / Q000187:drug effects / Q000503:physiopathology*
D002220:Carbamazepine; D005013:Ethosuximide