title: Imaging reveals the focal area of spreading depolarizations and a variety of hemodynamic responses in a rat microembolic stroke model.
abstract: Spreading depolarizations (SDs) occur in stroke, but the spatial association between SDs and the corresponding hemodynamic changes is incompletely understood. We applied multimodal imaging to visualize the focal area of selected SDs, and hemodynamic responses with SDs propagating over the ischemic cortex. The intracarotid infusion of polyethylene microspheres (d=45 to 53 μm) produced multifocal ischemia in anesthetized rats (n=7). Synchronous image sequences captured through a cranial window above the frontoparietal cortex revealed: Changes in membrane potential (voltage-sensitive (VS) dye method); cerebral blood flow (CBF; laser speckle contrast (LSC) imaging); and hemoglobin (Hb) deoxygenation (red intrinsic optical signal (IOS) at 620 to 640 nm). A total of 31 SD events were identified. The foci of five SDs were seen in the cranial window, originating where CBF was the lowest (56.9±9%), but without evident signs of infarcts. The hyperemic CBF responses to propagating SDs were coupled with three types of Hb saturation kinetics. More accentuated Hb desaturation was related to a larger decrease in CBF shortly after ischemia induction. Microsphere-induced embolization triggers SDs in the rat brain, relevant for small embolic infarcts in patients. The SD occurrence during the early phase of ischemia is not tightly associated with immediate infarct evolution. Various kinetics of Hb saturation may determine the metabolic consequences of individual SDs.
authors: 1] Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary [2] Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.
authors: Zsófia
authors: Z
authors: Bere
authors: Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
authors: Tihomir P
authors: TP
authors: Obrenovitch
authors: Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
authors: Gábor
authors: G
authors: Kozák
authors: Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
authors: Ferenc
authors: F
authors: Bari
authors: 1] Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary [2] Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.
authors: Eszter
authors: E
authors: Farkas
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000098:blood supply* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D013181:Cortical Spreading Depression; D003952:Diagnostic Imaging; D006439:Hemodynamics; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D020521:Stroke / Q000503:physiopathology