Formation of glutamate and GABA in epileptogenic tissue from human hippocampus in vitro.

The levels of some amino acids and the incorporation rates of 14C from glucose and acetate were estimated in control human brain tissue and epileptogenic foci from human hippocampus incubated in glucose-saline medium. In the epileptogenic tissue the level of glutamine and the incorporation of radioactivity from both substrates into glutamine were lowered, mainly from acetate. These results suggest damaged glial metabolism. The relative increase of glutamate and decrease of glutamate formation in epileptogenic tissue were similar to the changes caused in rat brain slices by increased concentration of potassium in the incubation medium.