A method for imaging endogenous release of two common neurotransmitters from tissue slices is described. This detection employs fluorometric, enzymatic assays for glutamate and for GABA, the progress of which is directly monitored by a cooled CCD camera. The assays are highly specific for their substrate, allowing accurate determination of either glutamate or GABA release by tissues. The images captured allow visualization of the release of these transmitters, permitting a direct correlation of transmitter release with well localized regions of the tissue examined. This procedure is advantageous for studies on endogenous neurotransmission.