Describe the role of the Na+/Ca2+ exchanger in neurons.

• A. NCX exchanges Ca2+ for Cl- at the plasma membrane.
• B. NCX imports Ca2+ into the neuron during signaling.
• C. NCX extrudes Ca2+ in exchange for Na+, helping Ca2+ homeostasis; reverse mode possible with high intracellular Na+, and Ca2+ triggers signaling.
• D. NCX is responsible for ATP production.

Answer: (C)