Glossary
Reuptake
What is reuptake?
Reuptake is how cells take neurotransmitters back in from the space around them, including the synaptic cleft between communicating cells. Neurotransmitters are chemical messengers that carry signals between neurons. Reuptake helps regulate how much of a messenger remains available to act on receptors.
How it works
The basic sequence is:
- Release: A neuron releases neurotransmitter into the space outside the cell, including a synaptic cleft.
- Receptor action: Available neurotransmitter can bind to receptors and change the receiving cell’s activity.
- Transporter-mediated clearance: Specialized membrane proteins move neurotransmitter back into cells. Depending on the transmitter, these may be the releasing neuron or nearby support cells called glia.
These processes overlap. Transporters do not wait until every molecule has “finished” signaling; uptake helps shape how much transmitter is available and for how long. Reuptake is one clearance route, while enzymes break down some messengers.
What do reuptake inhibitors do?
Some psychiatric medications act on these transporters. Selective serotonin reuptake inhibitors, or SSRIs, block serotonin reuptake and increase its availability outside cells.
Cocaine and amphetamines also affect dopamine transport, but their actions differ. Cocaine blocks dopamine uptake through the transporter. Amphetamine can enter through transporters and promote outward dopamine transport, increasing release into the extracellular space. Thus, increased dopamine outside cells does not imply that both drugs simply block the same recycling step. Their effects involve reward-related learning and motivation.
For the drug-mechanism distinction, see the review of psychostimulant effects on dopamine transmission and Kahlig and colleagues’ transporter experiment.