For example, UCP's alter the free calcium concentrations in the neuron.[1] Mitochondria are a major site of calcium storage in neurons, and the storage capacity increases with potential across mitochondrial membranes.[9][18] Therefore, when the uncoupling proteins reduce potential across these membranes, calcium ions are released to the surrounding environment in the neuron.[9] Due to the high concentrations of mitochondria near axon terminals, this implies UCP's play a role in regulating calcium concentrations in this region.[9] Considering calcium ions play a large role in neurotransmission, scientists predict that these UCP's directly affect neurotransmission.[9]