Salt in hypertension: physiological and molecular aspects

Salt loading acutely or chronically raises blood pressure in susceptible individuals. Sodium-dependent hypertension is characterized by sympathetic stimulation, apparently mediated via excitation of alpha 2-adrenergic receptors in brainstem nuclei. At this time, it is unclear which one(s) of the three alpha 2-adrenoceptor subtypes may be involved in this process. Although some studies have reported increases in numbers and/or functional responsiveness of alpha 2-adrenoceptors in hypertensives or normotensive offspring of hypertensive parents, others have failed to confirm this. Genetic analysis has suggested presence of alpha 2-adrenoceptor gene polymorphisms in some hypertensives but the results so far have been inconsistent.