Characterization of seizures in the flathead rat: a new genetic model of epilepsy in early postnatal development.
OBJECTIVE
Disorders in normal central nervous system (CNS) development are often associated with epilepsy. This report characterizes seizures in a novel genetic model of developmental epilepsy, the Flathead (FH) rat.


METHODS
Animals (n = 76) ages P0-22 were monitored for clinical and electrographic seizure activity. The effects of various AEDs on seizure frequency and duration also were assessed: phenobarbital (PB; 40 mg/kg), valproate (VPA; 400 mg/kg), or ethosuximide (ESM; 600 mg/kg).


RESULTS
FHs display episodes of behavior characterized by whole-body tremor, strub tail, alternating forelimb clonus, and complete tonus. EEG recordings from neocortex reveal that FH seizures are bilateral and begin around P7. Seizures occur at a frequency of approximately six per hour from P7 to P18 and the average duration of seizures increases through development. PB, VPA, and ESM failed to prevent seizures; however, PB significantly increased the interval of seizures but had no effects on the duration of seizures, whereas VPA decreased the duration of seizures and not the interval.


CONCLUSIONS
Seizures in FH rats occur at a constant and high frequency through a defined period in early postnatal development, and these seizures are not completely blocked by high doses of PB, VPA, or ESM. Because FH is a single-locus mutant displaying a highly regular pattern of seizure activity, it is an ideal model for examining the process of epileptogenesis in the developing brain, evaluating new AED therapies, and determining the identity of a gene essential to the normal development of cortical excitability.
Sarkisian
M R
MR
Department of Physiology and Neurobiology, University of Connecticut, Storrs 06269, USA.
Rattan
S
S
D'Mello
S R
SR
LoTurco
J J
JJ
D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000254:growth & development* / Q000503:physiopathology; D002540:Cerebral Cortex / Q000187:drug effects / Q000254:growth & development / Q000503:physiopathology; D004195:Disease Models, Animal; D004569:Electroencephalography / Q000187:drug effects; D004827:Epilepsy / Q000235:genetics / Q000503:physiopathology; D005013:Ethosuximide / Q000494:pharmacology; D005260:Female; D008297:Male; D008957:Models, Genetic; D009154:Mutation; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011922:Rats, Mutant Strains / Q000235:genetics*; D017208:Rats, Wistar / Q000235:genetics; D012640:Seizures / Q000235:genetics* / Q000503:physiopathology / Q000517:prevention & control; D014635:Valproic Acid / Q000494:pharmacology
D000927:Anticonvulsants; D005013:Ethosuximide; D014635:Valproic Acid; D010634:Phenobarbital