Cation-chloride cotransporters in neuronal communication

Two isoforms of the cation-Cl- cotransporter family are expressed in neurons and modulate neurotransmission. NKCC1, a Na+-K+-2Cl(-) cotransporter, by raising internal Cl-, is responsible for excitatory GABAergic activity in immature brain and in adult sensory neurons. KCC2, a neuronal-specific isoform of the K+-Cl- cotransporter, by lowering internal Cl- is critical for inhibitory GABA responses in mature central nervous system neurons.