The effect of changes in sound pressure level and frequency on the seizure response of audiogenic seizure susceptible rats.

An apparatus for pure tone stimulation of audiogenic seizure (AGS)-susceptible rats is described, and the effect of change in sound pressure level and frequency on AGS response in Uaz:AGS (SD) rats is shown. By use of pure tone stimulation, the prevalence of AGS response in rats of this strain, which have been bred for seizure-susceptibility, is 77%. With increasing frequency, the intensity-response curves show a shift to lower sound pressure levels, the ED50 for 20 kHz (83.8 dB) being significantly lower than the ED50 for 5 (110.5 dB) and 10 kHz (97.5 dB). Repeated exposure to seizure-inducing sound at weekly intervals leads to more severe seizures in individual rats. This should be taken into consideration as one possible confounding factor when using this method for assaying the efficacy of anticonvulsant drugs.