Daily repeated tetanic electrical stimulation (kindling) of hippocampus or other brain structures leads to progressive increase in epileptiform activity. Since kindling may involve changes in the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), the distribution of this amino acid was studied. A significant decrease in number of GABA immunoreactive positive cell bodies in stimulated CA1 region of the rat hippocampus compared to the contralateral side was found.