Figure 3.

High-level inhibition of complex III activity with antimycin A is required to increase the rate of glutamate release from depolarized synaptosomes. Synaptosomes (0.5 mg/ml) were preincubated at 37°C for 5 min before being depolarized with A 1 mM 4-aminopyridine or B 40 mM KCl. Rates of glutamate release at each concentration of antimycin A were plotted against percent inhibition of complex III activity brought about by that concentration of antimycin A. Freehand curves were drawn through the results. Points shown represent the mean ± SEM for experiments carried out in triplicate on at least 3 separate synaptosomal preparations.