Identification of GABAergic amacrine cell-like neurons developing in chick retinal monolayer cultures

Purified neuronal monolayer cultures were prepared from embryonic chick retinae. Using immunocytochemistry for GABA and autoradiographic demonstration of [3H]muscimol uptake as markers, approximately 32% of the cells were identified as putative in vitro counterparts of gamma-aminobutyric acidergic (GABAergic) amacrine cells. Whole cell patch clamp recordings revealed close similarities between identified [3H]GABA accumulating neurons in culture and amacrine cells recorded in retinal slices, with respect to voltage-dependent membrane currents and to ion channels gated by exitatory (N-methyl-D-aspartate, kainate, quisqualate, glutamate) and inhibitory (GABA, glycine) amino acid agonists. The results demonstrate that retinal neurons are able to differentiate in dissociated retinal cultures. Such cultures may thus serve as a model system to study development and function of CNS neurons.