Spontaneous occurrence of spike-wave discharges in five inbred strains of rats.

The number and the duration of the cortical registered spike-wave discharges were studied in four inbred strains of rats (G/Cpb, B/Cpb, BN/BiRij, ACI) and compared to those of the WAG/Rij strain. The latter strain is considered to be a model of absence epilepsy. Eight rats of each strain were recorded during a continuous period of 48 hours. An analysis of variance showed significant strain differences in both the number and the mean duration of spike-wave discharges. The value of both parameters increased in the following order: ACI less than BN/BiRij less than B/Cpb less than G/Cpb less than WAG/Rij, whereby the ACI strain was almost free of spike-wave discharges and the WAG/Rij strain showed a considerable number per hour. Since a clear strain difference between the five inbred strains emerged, the investigation of biological and genetic factors underlying these strain differences may provide useful information for absence epilepsy in humans.