Possible inhibition of focal cerebral ischemia by angiotensin II type 2 receptor stimulation

Masaru Iwai, Hong Wei Liu, Rui Chen, Ayumi Ide, Shoko Okamoto, Ryuji Hata, Masahiro Sakanaka, Tetsuya Shiuchi, Masatsugu Horiuchi

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Abstract

Background-The role of angiotensin II receptor subtypes was investigated in focal brain ischemia induced by middle cerebral artery (MCA) occlusion. Methods and Results-In Agtr2+ (wild-type) mice, MCA occlusion induced focal ischemia of ≈20% to 30% of the total area in coronal section of the brain. The ischemic area was significantly larger in angiotensin II type 2 receptor-deficient (Agtr2-) mice than in Agtr2+ mice. The neurological deficit after MCA occlusion was also greater in Agtr2- mice than in Agtr2+ mice. The decrease in surface cerebral blood flow after MCA occlusion was significantly exaggerated in the peripheral region of the MCA territory in Agtr2- mice. Superoxide production and NADPH oxidase activity were enhanced in the ischemic area of the brain in Agtr2 - mice. An AT1 receptor blocker, valsartan, at a nonhypotensive dose significantly inhibited the ischemic area, neurological deficit, and reduction of cerebral blood flow as well as superoxide production and NADPH oxidase activity in Agtr2+ mice. These inhibitory actions of valsartan were weaker in Agtr2- mice. Conclusions-These results suggest that AT2 receptor stimulation has a protective effect on ischemic brain lesions, at least partly through the modulation of cerebral blood flow and superoxide production.

Original languageEnglish
Pages (from-to)843-848
Number of pages6
JournalCirculation
Volume110
Issue number7
DOIs
Publication statusPublished - 17-08-2004

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All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Iwai, M., Liu, H. W., Chen, R., Ide, A., Okamoto, S., Hata, R., Sakanaka, M., Shiuchi, T., & Horiuchi, M. (2004). Possible inhibition of focal cerebral ischemia by angiotensin II type 2 receptor stimulation. Circulation, 110(7), 843-848. https://doi.org/10.1161/01.CIR.0000138848.58269.80