Models of Hypertension in Aging

There are both genetic and nongenetic models of hypertension in which the animals exhibit increases in blood pressure spontaneously or are genetically predisposed to increase blood pressure in response to a high-salt diet. Providing the strongest support for the theory that renal dysfunction in the excretion of sodium and water is the etiology of hypertension are observations that "hypertension follows the kidney." Men are generally at greater risk for cardiovascular and renal disease than are age-matched, premenopausal women. Various humoral and cardiovascular systems play a role in controlling blood pressure. Among them are the rennin-angiotensin-aldosterone system, endothelin, oxidative stress, obesity, and the sympathetic nervous system. The key system for controlling blood pressure and body fluid volume is the rennin-angiotensin-aldosterone system (RAAS.) Superoxide is known to interact with nitric oxide (NO) to cause quenching of NO and to produce peroxynitrite, one of the most potent oxidative compounds known. Endothelin is a potent vasoconstrictor that when infused chronically leads to increase in blood pressure.