Cytosolic and Mitochondrial Ca²⁺ Imaging in Drosophila Dopaminergic Neurons

The ATP-producing organelle mitochondrion controls cellular or synaptic Ca²⁺ concentrations through temporal uptake of Ca²⁺ outside of the mitochondria. Although intracellular Ca²⁺ influx occurs during neuronal activity, a persistently higher concentration of intracellular Ca²⁺ is neurotoxic. Healthy mitochondria ensure rapid Ca²⁺ uptake, which is necessary for proper neuronal activity. Mitochondrial Ca²⁺ buffering activity decreases in aged or sick neurons. In this chapter, we will introduce our protocol for evaluating Ca²⁺ buffering activity through the mitochondria during neuronal activity of dopaminergic neurons.