Electrophysiological and pharmacological characteristics of two types of spike-wave discharges in WAG/Rij rats

Rats of the WAG/Rij strain are commonly seen as a genetic model for general ised absence epilepsy in man. Interestingly, generalised absence epilepsy s hows, in addition to the fully generalised spike-wave discharges, a second type of spike-wave discharge, which lasts for a shorter time, has a lower f requency, and a lower incidence. The originally described distinction betwe en the two types of spike-wave discharges was mainly based on the shape, po larity and duration of the discharges. In the present study other character istics such as the spatial and temporal distribution of the spike and wave components of the two discharges and frequency spectra were found to differ between the two types. In addition, a reciprocal regulation of the two typ es of spike-wave discharges by drugs affecting the dopaminergic, system (ha loperidol and apomorphine) was observed. The results convincingly demonstra te the difference between the two phenomena and warrant the search for neur obiological mechanisms underlying both types of spike-wave discharges. (C) 2001 Published by Elsevier Science B.V.