Figure 5.

Kainate + Zn²⁺ exposure triggers selective mitochondrial depolarization (loss of Δψ) in Ca-A/K(+) neurons. Cultures were loaded with TMRE, switched into Ca²⁺-free buffer, and, after recording baseline fluorescence, were exposed for 10 min to 100 μM Zn²⁺ with 100 μM kainate (+10 μM MK-801; A), or were identically exposed but with the addition of rotenone (10 μM) 30 min before, during, and after the exposure (B). Cultures were then washed into Ca²⁺-free buffer containing 500 μM EDTA, 10 μM MK-801, and 10 μM NBQX. Fluorescence changes for each neuron are expressed as the ratio of fluorescence at each time point (F_x) to its own baseline fluorescence. Traces show the means ±SEM of TMRE fluorescence in mitochondrial-rich regions of ≥28 Ca-A/K(+) and ≥175 Ca-A/K(−) neurons from seven experiments each. Note the selective loss of TMRE fluorescence, indicative of loss of Δψ, in Ca-A/K(+) neurons (A) and enhanced loss of Δψ in both Ca-A/K(+) and Ca-A/K(−) neurons in the presence of rotenone (B).