title: Dilation of perforating arteries in rat brain in response to systemic hypotension is more sensitive and pronounced than that of pial arterioles: simultaneous visualization of perforating and cortical vessels by in-vivo microangiography.
abstract: Autoregulatory responses of perforating arteries play a key role in the maintenance of microcirculation of the deep brain regions. The aim of this study was to test our hypothesis that autoregulatory vasodilatation of perforating arteries is more effective than that of cortical arteries. We performed cerebral microangiography in adult Wistar rats using monochromatic synchrotron radiation at SPring-8 and for the first time radiographically visualized perforating arteries and cortical arteries simultaneously in a single view. In response to hypotension induced by arterial bleeding, both arteries showed significant vasodilatation. Steady-state responses of increments in caliber to stepwise hypotension revealed that perforating arteries exhibited significant vasodilatation at blood pressure below 80-99 mm Hg. Cortical arteries, on the other hand, showed a gradual and smaller vasodilatation beginning at 60-79 mm Hg. For the lowest blood pressure range at 40-59 mm Hg, the smallest arteries with a diameter of 20-40 microm showed maximal dilation in both groups, but perforating arteries showed significantly larger dilatation (185.0% of baseline diameter) than cortical arteries (152.7%; P=0.003). Our results indicate that vasodilatation of perforating arteries is more sensitive and pronounced in response to systemic hypotension than that of pial arteries, which explains how cerebral microcirculation is maintained efficiently in the deep brain regions.
authors.affiliation: Department of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshino
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakurai
authors.forename: Ximena-Sayuri
authors.initials: XS
authors.lastname: Oizumi
authors.forename: Taichi
authors.initials: T
authors.lastname: Akisaki
authors.forename: XiaoNan
authors.initials: X
authors.lastname: Wang
authors.forename: Koichi
authors.initials: K
authors.lastname: Yokono
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kondoh
authors.forename: Eiji
authors.initials: E
authors.lastname: Kohmura
authors.forename: Keiji
authors.initials: K
authors.lastname: Umentani
mesh_terms: D000818:Animals; D001160:Arterioles / Q000000981:diagnostic imaging / Q000503:physiopathology; D001794:Blood Pressure; D002533:Cerebral Angiography / Q000379:methods*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000098:blood supply / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation; D006706:Homeostasis; D007022:Hypotension / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D010841:Pia Mater / Q000098:blood supply / Q000000981:diagnostic imaging; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation