Figure 1.

Schematic outline of the proposed role for mitochondria (Mt) in synaptic release at the neuromuscular junction. Na⁺ influx through voltage gated Na⁺ channels (green) increases Na⁺ concentration in the presynaptic terminal, in turn triggering mitochondrial Ca²⁺ release through the mitochondrial Na⁺/Ca²⁺ exchanger (yellow). Ca²⁺ release triggers the fusion of presynaptic vesicles with the plasma membrane and the release of neurotransmitter. The released neurotransmitter binds to and opens acetylcholine receptors (blue) on the postsynaptic terminal.