Sodium–hydrogen exchanger 3 (NHE3)

Sodium–hydrogen exchanger 3 (NHE3) is a membrane transporter encoded by the SLC9A3 gene. It is primarily expressed on the apical surface of epithelial cells in the renal proximal tubule and small intestine. NHE3 mediates electroneutral exchange of extracellular sodium ions for intracellular hydrogen ions with a stoichiometry of 1:1. This process is essential for bulk reabsorption of filtered sodium in the kidney and for nutrient-independent sodium uptake in the gut. By regulating these exchanges, NHE3 plays a critical role in maintaining systemic fluid volume, blood pressure, acid-base balance, and overall electrolyte homeostasis. Its activity is tightly regulated by various kinases and interacting proteins; dysregulation or inhibition can lead to significant physiological effects relevant to hypertension management or treatment of constipation-predominant irritable bowel syndrome through drugs like tenapanor[1][2][4].

Other names

SLC9A3sodium–hydrogen antiporter 3NHE-3solute carrier family 9 member A3DIAR8

Inhibition of sodium reabsorption by blocking the Na+/H+ exchange activity in the intestine and kidney