Many studies have linked dietary salt intake with hypertension and harmful cardiovascular effects. Individuals who develop hypertension due to high salt intake have kidneys with limited capacity to excrete daily absorption and tend to retain salt in the skin and other extracellular compartments (Titze et al, 2003). Aldosterone plays an important role in regulating the body's salt and water balance by controlling the activity of epithelial sodium channels in the renal collecting duct and can cause swelling and stiffening of the vessel while also altering the production of nitric oxide, which affects the ability of the vessel to vasodilate. (Nagata, 2006). Salt consumption leads to a transient increase in plasma volume and a subsequent increase in blood pressure as extracellular volume returns to normal (Hamlyn et al, 1986). It has recently been stated that plasma sodium plays a primary role in blood pressure control due to its discovered increase (23-69 mg) in subjects with hypertension (He et al, 2004). From this discovery arose the idea that the vascular endothelium might participate in sodium-mediated blood vessel function through the response of endothelial cells to aldosterone. To support the claim that endothelial stiffness is affected by changes in plasma concentration, atomic force microscopy measuring endothelial cell stiffness was used to see what happens in the absence of aldosterone. The endothelial cell samples were stored in two different environments: an infusion of eplerenone, which created an aldosterone-free culture medium, and another medium that contained aldosterone. The results showed that the stiffness and deformability of endothelial cells were unchanged in the aldosterone-free environment... middle of paper... that sodium ingestion (especially in high contents) passes through extracellular compartments including the vascular system before being eliminated by the kidneys. An acute increase in plasma sodium concentration can alter the mechanical properties of the vascular endothelium, provided aldosterone is present. Aldosterone not only plays an important role in regulating sodium and potassium transport in the kidneys but also in the cardiovascular system. Sodium accumulates in the extracellular space when the kidneys fail to adequately regulate salt excretion based on salt absorption and/or when the aldosterone concentration increases, leading to an increase in plasma sodium concentration. An important finding in these studies was the observed effects of amiloride, which acted by blocking sodium channels and preventing an increase in stiffness by reversing the increase in cell volume and pressure.