Long-term low salt diet increases blood pressure by activation of the renin-angiotensin and sympathetic nervous systems.
Background The aim of this study was to investigate the effect of long-term low salt diet on blood pressure and its underlying mechanisms.Methods Male Sprague-Dawley (SD) rats were divided into normal salt diet group (0.4%) and low salt diet group (0.04%). Blood pressure was measured with the non-invasive tail-cuff method. The contractile response of isolated mesenteric arteries was measured using a small vessel myograph. The effects on renal function of the intrarenal arterial infusion of candesartan (10 μg/kg/min), an angiotensin II receptor type 1 (AT1R) antagonist, were also measured. The expressions of renal AT1R and mesenteric arterial α1A, α1B, and α1D adrenergic receptors were quantified by immunoblotting. Plasma levels of angiotensin II were also measured.Results Systolic blood pressure was significantly increased after 8 weeks of low salt diet. There were no obvious differences in the renal structure between the low and normal salt diet groups. However, the plasma angiotensin II levels and renal AT1R expression were higher in low than normal salt diet group. The intrarenal arterial infusion of candesartan increased urine flow and sodium excretion to a greater extent in the low than normal salt diet group. The expressions of α1A and α1D, but not α1B, adrenergic receptors, and phenylephrine-induced contraction were increased in mesenteric arteries from the low salt, relative to the normal salt diet group.Conclusion Activation of the renin-angiotensin and sympathetic nervous systems may be involved in the pathogenesis of long-term low salt diet-induced hypertension.
['Wang|Jialiang|J|', 'Deng|Yi|Y|', 'Zou|Xue|X|', 'Luo|Hao|H|', 'Jose|Pedro A|PA|', 'Fu|Chunjiang|C|', 'Yang|Jian|J|', 'Zeng|Chunyu|C|']
D000818:Animals D001794:Blood Pressure D004039:Diet, Sodium-Restricted D004195:Disease Models, Animal D005500:Follow-Up Studies D006973:Hypertension D008297:Male D008638:Mesenteric Arteries D051381:Rats D017207:Rats, Sprague-Dawley D012083:Renin D012084:Renin-Angiotensin System D013564:Sympathetic Nervous System D013997:Time Factors D014661:Vasoconstriction
low salt diet sympathetic nervous system sodium excretion Hypertension renin-angiotensin system vascular contraction