A loss of GABAergic hippocampus innervation in rats with cobalt-induced epilepsy demonstrated by Wolman's fluorescence method.

The topohistochemistry of gamma-aminobutyric acid (GABA) was studied in the hippocampus of rats with epileptiform activity provoked by cortical implantation of cobalt-agar pellets and in control rats with implanted agar-pellets. Using the GABA specific fluorochroming procedure of Wolman (1971) a distinct decrease of GABA fluorescence was found especially in the pyramidal and granular layer, but only in the animals with a typical epileptiform activity of the EEG. The results support the hypothesis that there is a lack of GABAergic inhibition in epileptic individuals, but the anticonvulsive effect of GABA depends on structural and functional relations in the specific type of seizure.