Glutamate transporters from brain. A novel neurotransmitter transporter family.

The removal of neurotransmitters by their transporters in presynaptic nerve terminals and glial cells plays an important role in the termination of synaptic transmission. Many neurotransmitter transporters, which are sodium- and chloride-coupled, have been cloned and shown to constitute a large superfamily. Glutamate is the major excitatory neurotransmitter in the central nervous system. If not efficiently removed, it causes death of neuronal cells. Its transporter couples the flow of glutamate to that of sodium and potassium. Recently three different but related glutamate transporters have been cloned, which have no significant homology to the members of the superfamily.