What is the process by which a neurotransmitter returns to the sending neuron after signaling?

• A. Diffusion
• B. Synthesis
• C. Secretion
• D. Reuptake

Answer: (D)

After a signal is sent, the neurotransmitter must be cleared from the synapse to stop the message. The return of the transmitter to the sending neuron is reuptake. Transporter proteins on the presynaptic membrane pull the released molecules back into the neuron, where they can be recycled for future releases. This quickly terminates signaling and helps regulate neurotransmitter levels.

Diffusion can move transmitter out of the gap, but it’s slower and less precise for ending the signal. Synthesis is about making the transmitter before release, not returning it after signaling. Secretion is the release of the transmitter into the synapse, not its reabsorption.