Effects of high salt diets and taurine on the development of hypertension in the stroke-prone spontaneously hypertensive rat

Taurine is present in high concentrations in mammalian tissues and has been implicated in cardiovascular control mechanisms. The aim of the present st udy was to evaluate the ability of taurine to attenuate salt-induced elevat ions in blood pressure and markers of damage to the kidney and cardiovascul ar system in stroke prone spontaneously hypertensive rats (SPSHR). Male SPS HR (6 weeks old) were placed on high salt diets that contained 1% (w/w) NaC l added to their normal chow for 84 days and then were switched to 3% added NaCl for the remaining 63 days of the study. SPSHR was given 1.5% taurine in the drinking water (n = 8), a taurine free diet (n = 8) or normal chow ( n = 8). A final control group (n = 6) was not given high salt diets. High s alt diets caused an acceleration in the development of hypertension in all groups. Taurine supplementation reduced ventricular hypertrophy and decreas ed urinary excretion of protein and creatinine. The taurine free diet did n ot alter serum or urinary excretion of taurine, but did result in elevated urinary nitrogen excretion, increased serum cholesterol levels, and impaire d performance in a spatial learning task. Alterations in dietary taurine in take did not alter urinary or serum electrolytes (Na+, K+), but taurine sup plementation did attenuate a rise in serum calcium seen with the high salt diets. Urinary excretion (mug/24h) of epinephrine and dopamine was signific antly reduced in SPSHR given 1% NaCl in the diet, but this effect was not s een in SPSHR on taurine free or supplemented diets. Taurine supplementation showed cardioprotective and renoprotective effects in SPSHR given high sal t diets.