Radiation-controlled focal pharmacology in the therapy of experimental epilepsy

Radiation-controlled focal pharmacology is a method using intermediate-dose radiation of a portion of the brain to break down the blood-brain barrier (BBB) followed by the administration of a drug which does not cross the normal BBB but which has a desired pharmacologic effect when it does cross the BBB. Therefore, the drug affects only the radiated portion of the brain. Cats with alumina-cobalt chronic epileptic foci were given intravenous gamma-aminobutyric acid (GABA) with no suppression of their EEG-recorded, computer-analyzed epileptic spike frequency. When the focus received 6,000 rad of Bragg peak proton radiation, there was no significant change in spike frequency. Then, however, when GABA was again given, there was dramatic suppression of spike frequency, reaching a peak of 87% suppression at 9 days postradiation. The efficacy of GABA used in radiation-controlled focal pharmacology in the 7- to 9-day postradiation period was demonstrated with a confidence of p less than 0.01.