GLOMERULAR-BASEMENT-MEMBRANE POLYANIONIC SITES AND NITRIC-OXIDE IN GENETICALLY SALT-SENSITIVE AND RESISTANT HYPERTENSIVE RATS

Cationic colloid gold, a polycationic histochemical probe, was used to analyze the distribution of glomerular basement membrane (GBM) polyan ions, including heparan sulfate protoglycan in genetic salt-sensitive (SBH/Y) and resistant (SBN/Y) hypertensive rats, with or without high dietary salt intake. GBM morphology, renal function and nitric oxide, as measured by plasma and urine nitrite (NO2) and nitrate (NO3) were a lso determined. In the sail-sensitive rats the high-salt dietary intak e resulted in severe hypertension, proteinuria and decreased glomerula r filtration rate. After 1 month of high-salt intake, the average widt h the GBM of salt-sensitive rats was higher by 27% than that of salt-r esistant rats. The number of GBM anionic sites (lamina rata externa an d interna) was much lower in both salt-sensitive and salt-resistant gr oups after 1 month of salt loading, 8.04+/-0.36 and 7.8+/-0.25 counts/ cm, respectively, compared to the respective values of non-salt-loaded animals, 20.58+/-1.08 counts/cm in the SBH/Y (p<0.001) and 21+/-1.86 counts/cm in the SBN/Y (p<0.001). A decreased nitric oxide production was found in the salt-sensitive rats before and after salt loading com pared with the salt-resistant group. No correlation was found between the nitric oxide changes and the GBM modifications. It is concluded th at high-salt intake may be deleterious to the permselectivity of the G BM. It is suggested that salt restriction in hypertension may have a b eneficial effect in preventing GBM permselectivity changes and protein uria.