22 research outputs found
High salt diet impairs cerebral blood flow regulation via saltâinduced angiotensin II suppression
ObjectivesThis study sought to determine whether saltâinduced ANG II suppression contributes to impaired CBF autoregulation.MethodsCerebral 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, modelâfree analysis, and a mechanistic theoretical model of blood flow through cerebral arterioles.ResultsAutoregulation was intact in LSâfed animals as MAP was reduced via graded hemorrhage to approximately 50Â mm Hg. Shortâterm (3Â days) and chronic (4Â 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 (5Â mg/kg/min, i.v.) restored CBF autoregulation between the preâhemorrhage MAP and 50Â mm Hg in rats fed shortâterm HS diet. Mechanisticâbased model analysis showed a reduced myogenic response and reduced baseline VSM tone with shortâterm HS diet, which was restored by ANG II infusion.ConclusionsShortâterm and chronic HS diet lead to impaired autoregulation in the cerebral circulation, with saltâinduced ANG II suppression as a major factor in the initiation of impaired CBF regulation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149286/1/micc12518_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149286/2/micc12518.pd