Prostaglandin E1-induced latent epileptogenic foci

Suprafusion of 125 microliter 6% KCl solution over the visual cortex of rabbits 2-24 h after they suffered a prostaglandin (PG) E1-induced epileptic seizure was found to cause a recurrence of seizure activity. The initial seizure was induced by the cortical suprafusion of PGE1 over the left visual cortex of PG transport inhibitor-pretreated rabbits. Control animals that were not pretreated with PG transport inhibitors (bromcresol green or probenecid), or received suprafusion of saline or PGF2 alpha rather than PGE1, did not show initial seizure activity. In these animals, and in animals that had PG-induced seizures 72 h before KCl administration, the KCl solution caused only inhibition of the visually evoked response but no seizure activity. The results are interpreted to indicate that under appropriate conditions PGE1 can create a latent epileptogenic focus which can be reactivated by KCl. It is suggested that since PGE1 is produced by the brain normally, and in increased amounts as the result of overstimulation, irritation or trauma, this potent autacoid may play a role in the spontaneous development of latent epileptogenic foci or the recurrence of epileptic seizures.