Na-K-Cl cotransporter

Na-K-Cl cotransporter (NKCC) is a type of solute carrier protein that facilitates the transport of sodium (Na), potassium (K), and chloride (Cl) ions across the cell membrane. There are two known types of NKCCs: NKCC1 and NKCC2, each with distinct functions and locations within the body.

Function

NKCCs play a crucial role in maintaining homeostasis within the body by regulating the concentrations of Na, K, and Cl ions in cells. They do this by using the energy from the Na+/K+ pump to transport these ions against their concentration gradients.

NKCC1 is found in many tissues throughout the body, including the brain, spinal cord, and heart. It is involved in a variety of physiological processes, such as cell volume regulation, neuronal excitability, and the secretion of chloride in various tissues.

NKCC2, on the other hand, is primarily found in the kidney where it plays a key role in the reabsorption of sodium, potassium, and chloride in the nephron, the functional unit of the kidney. This process is essential for the regulation of blood pressure and body fluid volume.

Clinical significance

Abnormalities in the function of NKCCs can lead to a variety of health conditions. For instance, mutations in the gene encoding NKCC2 can cause a rare type of Bartter syndrome, a disorder characterized by low levels of potassium in the blood, increased levels of aldosterone, and normal to low blood pressure.

Inhibition of NKCC1 has been proposed as a potential treatment for conditions such as epilepsy, chronic pain, and tinnitus, as these conditions have been linked to increased neuronal excitability due to elevated levels of intracellular chloride.

See also

• Solute carrier family
• Cell membrane
• Homeostasis
• Na+/K+ pump
• Bartter syndrome