High Quality Content by WIKIPEDIA articles! A reuptake inhibitor (RI), also known as a transporter blocker, is a drug that inhibits the plasmalemmal transporter-mediated reuptake of a neurotransmitter from the synapse into the pre-synaptic neuron, leading to an increase in the extracellular concentrations of the neurotransmitter and therefore an increase in neurotransmission. Various drugs utilize reuptake inhibition to exert their psychological and physiological effects, including many antidepressants and psychostimulants.