NKCC1 is one of two Na-K-Cl cotransporter isoforms that have been identified. NKCC1 is present in a wide variety of secretory epithelia and non-epithelial cells. NKCC1 is expressed in virtually all mammalian cells and is thought to play a housekeeping role in cell volume homeostasis and the common control of cytosolic ion content. NKCC1 does not use ATP but operates using electrochemical gradient for Na+ and K+ produced by Na+-K+-ATPase4. There is considerable evidence that uptake of Cl− in immature neurons is mediated by NKCC1. High expression of NKCC1 in immature neurons plays an important role in maintaining high intracellular Cl−
