Association of NMDA receptor sites and seizures of El mice.

To investigate the possible role of N-methyl-D-aspartate (NMDA) receptors in the seizures of El mice, a genetic animal model of epilepsy, we measured [3H]3-[(+)-2-(carboxypiperazin-4-yl)][1,2-3H]- propyl-1-phosphonic acid (CPP) binding in several brain regions of El and ddY mice. At 22-24 weeks of age, the maximum number of binding sites (Bmax) of [3H]CPP was lower only in the cerebral cortex of both stimulated and unstimulated El mice (El(+) and El(-), respectively) than in that of ddY mice. A reduction in Bmax values of cortical [3H]CPP binding of El mice was detected after the age of 12 weeks. Cortical [3H]CPP binding in El(+) mice decreased further transiently after evoked seizures. No significant change was observed in El(-) mice after postural stimulation. These results suggest that El(+) and El(-) mice share seizure propensity and that activation of NMDA receptors is involved in the seizures of El mice.