Four and even 8% sodium chloride diets are commonly used; for instance, it was demonstrated that Dahl SS rats on an 8% NaCl diet had similar plasma sodium and protein levels compared to those on a 0.3% salt diet (and salt-resistant Dahl R rats on 8% diet), whereas their urine flow and sodium excretion rates were significantly higher as measured in pressure-natriuretic response studies (Roman and Kaldunski, 1991; Kakizoe et al., 2009). We have also shown that Dahl SS rats maintain stable plasma sodium and potassium levels when switched to 8% NaCl (Pavlov et al., 2013). We conclude that the rats could tolerate even such a high salt load as 8% NaCl chow when they have unlimited access to fresh water.