[Role of electrolytes in the development and maintenance of hypertension]

Sodium (Na) intake is one of the important environmental factors influencing the development and maintenance of high blood pressure (BP). Patients with essential hypertension can be divided into two groups: "salt-sensitive" and "non-salt-sensitive", according to BP response to salt loading, suggesting the heterogeneity of salt sensitivity of BP. Salt-sensitive patients had greater increases in BP by salt loading, associated with greater Na retention. Although the precise mechanism for impaired renal Na handling in salt-sensitive patients is still unknown, the sympathetic nervous system in the kidney may play an important role in the decreased renal function of Na excretion and the increased salt sensitivity. Moreover, there are several pieces of evidence indicating that increased renal sympathetic nerve activity is intimately related to the abnormal central noradrenergic systems. In addition, the renin-angiotensin system, insulin, and so on, may modulate salt sensitivity of BP. Some ions influence the hypertensinogenic effect of Na: Chloride ion facilitates it, while potassium, calcium and magnesium antagonize it. Moreover, obesity and a stressful environment increase salt sensitivity of BP.