DIETARY-SODIUM INTAKE AND CARDIAC NERVE-CELL HYPERTROPHY IN WISTAR RATS

We determined the effect of dietary sodium intake (0.15 and 8% NaCl) o n the cardiac neuron size of normotensive 3-week old Wistar rats. An i ncrease in dietary sodium for 48 weeks induced an increase in neuronal size. The number of large neurons (larger than 500 mu m(2)) increased significantly (chi-square test) in rats ingesting 8% NaCl in their fo od. The rats presented hypertension (128 +/- 9 vs 134 +/- 16 mmHg; dif ference not significant, Student t-test) and a statistically significa nt 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 a n increase of cardiac muscle mass.