We have examined the uptake of [3H]GABA by isolated glial (Müller) cells using light microscope autoradiography. The aim of these studies was to determine whether Müller cells dissociated from papain-treated mouse retina have the capacity to accumulate exogenous GABA and to further characterize the uptake process. Our results show that isolated Müller cells retain the capacity to accumulate exogenous [3H]GABA and this uptake is inhibited by excess GABA, DABA and beta-alanine. This communication also describes a new method for performing light microscope autoradiography.