Dietary sodium intake and cardiac nerve cell hypertrophy in Wistar rats

We determined the effect of dietary sodium intake (0.15 and 8% NaCl) on the cardiac neuron size of normotensive 3-week old Wistar rats. An increase in dietary sodium for 48 weeks induced an increase in neuronal size. The number of large neurons (larger than 500 microns 2) increased significantly (chi-square test) in rats ingesting 8% NaCl in their food. The rats presented hypertension (128 +/- 9 vs 134 +/- 16 mmHg; difference not significant, Student t-test) and a statistically significant increase in cardiac muscle mass (1.6 +/- 0.1 vs 2.0 +/- 0.2 mg/g of rat). We conclude that food sodium can significantly increase cardiac nerve cell size and this trophic response occurs concomitantly with an increase of cardiac muscle mass.