GABA imaging in brain slices using immobilized enzyme-linked photoanalysis

GABA plays an important role in inhibitory neurotransmission. In the developing brain, GABA also acts as a paracrine chemical mediator. To evaluate the ambient GABA gradients in the brain, an enzyme-linked imaging system that consisted of GABase and NADP+ was developed. In rat cerebellar slices, GABA release was observed in the layers containing GABAergic neurons. In telencephalic slices from embryonic GAD67-GFP knock-in mice, ambient GABA levels were high in the ganglionic eminence, where GABA cells are generated, but missing in homozygotes. This study indicates that this method will be useful to study the topography and dynamics of ambient GABA concentrations.