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High salt diet impairs cerebral blood flow regulation via salt‐induced angiotensin II suppression
Author(s) -
Allen Linda A.,
Schmidt James R.,
Thompson Christopher T.,
Carlson Brian E.,
Beard Daniel A.,
Lombard Julian H.
Publication year - 2019
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1111/micc.12518
Subject(s) - salt (chemistry) , cerebral blood flow , angiotensin ii , chemistry , endocrinology , medicine , renin–angiotensin system , microbiology and biotechnology , biology , blood pressure
Objectives This study sought to determine whether salt‐induced ANG II suppression contributes to impaired CBF autoregulation. Methods Cerebral autoregulation was evaluated with LDF during graded reductions of blood pressure. Autoregulatory responses in rats fed HS (4% NaCl) diet vs LS (0.4% NaCl) diet were analyzed using linear regression analysis, model‐free analysis, and a mechanistic theoretical model of blood flow through cerebral arterioles. Results Autoregulation was intact in LS ‐fed animals as MAP was reduced via graded hemorrhage to approximately 50 mm Hg. Short‐term (3 days) and chronic (4 weeks) HS diet impaired CBF autoregulation, as evidenced by progressive reductions of laser Doppler flux with arterial pressure reduction. Chronic low dose ANG II infusion (5 mg/kg/min, i.v.) restored CBF autoregulation between the pre‐hemorrhage MAP and 50 mm Hg in rats fed short‐term HS diet. Mechanistic‐based model analysis showed a reduced myogenic response and reduced baseline VSM tone with short‐term HS diet, which was restored by ANG II infusion. Conclusions Short‐term and chronic HS diet lead to impaired autoregulation in the cerebral circulation, with salt‐induced ANG II suppression as a major factor in the initiation of impaired CBF regulation.