ALTHOUGH glutathione (GSH) is considered an important antioxidant in the brain, its cellular localization is unclear. In general, neurones are supposed to contain considerably less GSH than astrocytes. We determined biochemically and immunocytochemically the presence of GSH in cultured neurones and astrocytes from the cortex, mesencephalon and striatum. Cortical neurones contained less GSH than astrocytes whereas GSH levels in neurones from the striatum and mesencephalon were comparable to those in astrocytes. Immunocyto-chemistry showed significant GSH staining in neurones. Fluorescent double staining of GSH and tyrosine hydroxylase revealed that dopaminergic neurones also contained GSH, although apparently at a lower level than other mesencephalic neurones.