Changes in [3H]lysine incorporation into protein in a seizure focus in rat isocortex.

A focus of epileptiform discharge was induced in rat isocortex by subpial injection of 5 microliters of 100 mM FeCl3. Control animals were prepared with saline injections. Protein synthesis was estimated by uptake of [3H]lysine and its incorporation into protein at the site of iron injection, in the contralateral homotopic isocortex, and in the midline cerebellum. We found diminished uptake of [3H]lysine into all regions of rat brain in the interictal or nonseizing iron-injected animals, whereas the corrected rate of incorporation of [3H]lysine into protein was not significantly different from control rates. Actively seizing animals showed no inhibition of uptake of [3H]lysine, but [3H]lysine incorporation into protein relative to the uptake was significantly inhibited within the epileptic focus but not in the other areas examined. This decreased incorporation of amino acids into protein parallels that found in animals convulsing after electroshock or pentylenetetrazol injection.