Dietary sodium intake and cardiac nerve cell hypertrophy in Wistar rats

We determined the effect of dietary sodium intake (0.15 and 8 per cent 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 muM2) increased significantly (chi-square test) in rats ingesting 8 per cent NaCl in their food. The rats presented hypertension (128 ñ 9 vs 134 ñ 16 mmHg; difference not significant, Student t-test) and a statistically significant increase in cardiac muscle mass (1.6 ñ 0.1 vs 2.0 ñ 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.