Jane F. Reckelhoff, Radu Iliescu, Licy Yanes, and Lourdes A. Fortepiani
All forms of hypertension studied to date are caused by a defect in the handling of sodium and water by the kidney. There is a shift to the right in the pressure-natriuresis relationship (higher blood pressure) in which a hypertensive individual must increase blood pressure in order to excrete a normal sodium load. There are sex differences in blood pressure control in humans and animals, with males having higher blood pressure than females. However, blood pressure increases in some women after menopause. The mechanisms that play a role in hypertension, and have been studied extensively, include the renin-angiotensin-aldosterone system, endo-thelin, oxidative stress, the sympathetic nervous system, androgen/estrogen ratio, and obesity.
Rats and mice are commonly used for the study of hypertension and 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. Some of these models have been used for aging studies. The nongenetic models of hypertension are produced in normotensive rats by maneuvers that will increase their blood pressure. Many of these maneuvers could be performed in aging animals. There are also transgenic rat and mouse models that may be suitable for aging studies, but to date have not been used in aging studies. Therefore, their suitability remains to be determined experimentally.
The study of aging in hypertension is limited mainly to rats and mice since these animals have relatively short life spans, are inexpensive to purchase and maintain, and can be easily manipulated. This chapter will focus on genetic and nongenetic models of hypertension in rats and transgenic models of hypertension in rats and mice. There are few studies of aging in hypertensive animals. Therefore, in this chapter the most common hypertensive models used will be discussed along with other models that could be used but have not been in the past.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...