The histochemical localization of GABA-transaminase in the efferents of the striatum.

The striatum is known to contain GABA neurons projecting to the globus pallidus, entopeduncular nucleus and substantia nigra. Following lesions of striatal neurons with kainic acid, we have observed a decrease in the histochemically detectable activity of GABA-transaminase, the enzyme responsible for GABA catabolism, in both the striatum and in those areas to which it is known to send GABA projections. These results suggest that GABA-transaminase may be contained in striatal GABA neurons and thus that GABA-transaminase histochemistry may be a useful adjunct to the biochemical demonstration of GABA pathways in the brain.