title: Rapid and local autoregulation of cerebrovascular blood flow: a deep-brain imaging study in the mouse.
abstract: The brain obtains energy by keeping the cerebral blood flow constant against unexpected changes in systemic blood pressure. Although this homeostatic mechanism is widely known as cerebrovascular autoregulation, it is not understood how widely and how robustly it works in the brain. Using a needle-like objective lens designed for deep-tissue imaging, we quantified the degree of autoregulation in the mouse hippocampus with single-capillary resolution. On average, hippocampal blood flow exhibited autoregulation over a comparatively broad range of arterial blood pressure and did not significantly respond to pressure changes induced by the pharmacological activation of autonomic nervous system receptors, whereas peripheral tissues showed linear blood flow changes. At the level of individual capillaries, however, about 40% of hippocampal capillaries did not undergo rapid autoregulation. This heterogeneity suggests the presence of a local baroreflex system to implement cerebral autoregulation.
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Nahoko
authors.initials: N
authors.lastname: Kuga
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hirata
authors.forename: Ikuko
authors.initials: I
authors.lastname: Sakai
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Tanikawa
authors.forename: Huei Yu
authors.initials: HY
authors.lastname: Chiou
authors.forename: Takuma
authors.initials: T
authors.lastname: Kitanishi
authors.forename: Norio
authors.initials: N
authors.lastname: Matsuki
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ikegaya
mesh_terms: D000818:Animals; D001776:Blood Circulation Time / Q000295:instrumentation / Q000379:methods; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D016650:Fluorescein-5-isothiocyanate / Q000032:analysis; D006706:Homeostasis / Q000502:physiology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods; D013997:Time Factors
chemical_list: D016650:Fluorescein-5-isothiocyanate