Valsartan improves the lower limit of cerebral autoregulation in rats

Junichi Takada, Setsuro Ibayashi, Hiroaki Ooboshi, Tetsuro Ago, Eiichi Ishikawa, Masahiro Kamouchi, Takanari Kitazono, Mitsuo Iida

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

The effects of angiotensin II type 1 receptor blockers (ARBs) on cerebral blood flow (CBF) autoregulation have not been fully clarified. Thus, we examined the acute effect of valsartan, the most selective ARB, on CBF autoregulation in spontaneously hypertensive rats. Intravenous administration of valsartan (0.3 mg/kg) reduced the mean arterial pressure (MAP) from 184±5 (mean±SEM) to 174±5 mmHg (p<0.001) without affecting CBF as measured by laser-Doppler flowmetry. The lower limit of CBF autoregulation (the MAP at which the CBF was 80% of the baseline value) in the valsartan-treated group (122±3 mmHg) was significantly lower than that in the control group (135±4 mmHg, p<0.05). Reverse transcribed-polymerase chain reaction and immunohistochemical staining demonstrated that both anglotensin II type 2 receptors and angiotensin II type 1 receptors (AT1Rs) were expressed in endothelial and smooth muscle cells of the rat cerebral arteries. These results suggest that specific inhibition of AT1Rs in the cerebral circulation causes the leftward shift of the lower limit of autoregulation.

Original languageEnglish
Pages (from-to)621-626
Number of pages6
JournalHypertension Research
Volume29
Issue number8
DOIs
Publication statusPublished - Aug 1 2006

All Science Journal Classification (ASJC) codes

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

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