A method for imaging endogenous release of two common neurotransmitter
s from tissue slices is described. This detection employs fluorometric
, enzymatic assays for glutamate and for GABA, the progress of which i
s directly monitored by a cooled CCD camera. The assays are highly spe
cific for their substrate, allowing accurate determination of either g
lutamate or GABA release by tissues. The images captured allow visuali
zation of the release of these transmitters, permitting a direct corre
lation of transmitter release with well localized regions of the tissu
e examined. This procedure is advantageous for studies on endogenous n
eurotransmission. (C) 1998 Elsevier Science B.V. All rights reserved.