Blood pressure and sympathetic nervous function in spontaneously hypertensive rats derived from breeders on low...

We investigated the effect of dietary salt restriction in spontaneously hypertensive rat (SHR) breeders to determine if the development of hypertension of offspring would be blunted. Weaning SHRs (F-0) were divided into 3 groups and were given a diets containing sodium of 0.4% (G 1), 0.05% (G 2), or 0.4% plus mefruside 0.001% (G 3) with distilled water. Potassium content was 0.75% and the other ingredients except chloride were identical in all the diets. Offsprings (F-1) were derived from selective inbreeding within each group. Systolic blood pressure rose over 160 mmHg by 8 weeks of age in all the male rats of all the groups in both F-0 and F-1. There was no difference in blood pressure between G 1 and G 2 at any age, while in G 3 blood pressure was significantly lower than in G 1 at 12 and 20 weeks of age in F-1. The findings in pressure were ascertained by heart-body weight ratio determined at autopsy, which was similar between G 1 and G 2, and was smaller in G 3 than the others at 20 weeks of age. Aldostrone excretion rate was markedly higher in G 2 than G 1 and G 3 at all study points, whereas plasma renin content was similar between G 1 and G 2, and higher in G 3. Plasma concentrations of noradrenaline and adrenaline did not differ among the 3 groups at any age in both F-0 and F-1.(ABSTRACT TRUNCATED AT 250 WORDS)