Kindling Susceptibility and Genetic Seizure Predisposition in Inbred Mice

Abstract

Olfactory bulb kindling rates were studied in two inbred strains of genetically seizure-prone mice (DBA/2 and El) and in three non-epileptic inbred strains [C57BL/6 (B6), ddY, and C3H/He (C3H)]. None of the DBA/2 mice had been stimulated to seizure before or during the kindling and all mice were studied at 4-6 weeks of age, before development of spontaneous or movement-induced seizure activity in the El strain. The audiogenically seizure-susceptible DBA/2 mice required the fewest number of stimulations to reach stage 5 seizure (mean +/- SE = 4.0 +/- 0.6). The nonepileptic C3H mice required the most stimulations to reach stage 5 seizures (22.6 +/- 1.4). Kindling rates for B6 (9.6 +/- 0.6), El (14.8 +/- 1.1), and ddY (18.5 +/- 1.0) strains were intermediate, and the kindling rate for each strain was significantly different from that of the other strains. These findings show that the seizure-susceptible El mouse kindles more rapidly than the genetically similar but nonepileptic ddY control and suggest that an inherited seizure susceptibility accelerates the kindling rate. Nonepileptic B6 mice kindled more rapidly than El mice, however, suggesting that genetic factors other than those that influence seizure susceptibility are of primary importance in the determination of the kindling rate.