Fig. 5.
Calibration of NADH fluorescence.A, NADH fluorescence signal resulting from mixing known concentrations of glutamate with GDH saline (circlesrepresent the mean of two measurements at each glutamate concentration). Note there is a logarithmic relationship between glutamate concentration and NADH fluorescence. B, Frequency distribution histogram of the NADH fluorescence levels after stimulation of astrocytes. For each experiment (n = 10), we randomly chose 13 regions in the optical field from which to measure the NADH intensity. The peak change of fluorescence in each region was measured. Comparison of A withB allows an estimate of the glutamate levels surrounding astrocytes. The amplitude of NADH fluorescent signals is expressed as a percent change in dF/Fo.