DIETARY-SODIUM INDUCED CARDIAC-HYPERTROPHY

In humans, high sodium intake not only increases the blood pressure, and thus can cause left ventricular hypertrophy (LVH), but also appears to increase LVH independent of this increase in blood pressure. In both normo- and hyper-tensive rats the hypertrophic effect of increased dietary sodium intake on the heart has been clearly established. In normotensive rats, this effect is strain and age dependent, and seems independent of hemodynamic effects of high sodium intake. In both rats and humans, dietary sodium appears to increase wall thickness, resembling pressure overload rather than an increased left ventricular diameter as expected of volume overload. The mechanisms through which high dietary sodium induces hypertrophy are still unknown. It is possible that dietary sodium increases either adrenergic stimulation and (or) enhances sensitivity for adrenergic stimulation and that this hypertrophic response mainly acts via stimulation of alpha-1-adrenergic receptors. Stimulation of the alpha-1-adrenergic receptors will increase the inositol phosphate - diacyl glycerol pathway and enhance the Na+/H+ exchange. The activity of this exchanger might play an important role in the development of dietary sodium induced cardiac hypertrophy.