title: Impact of aging on spreading depolarizations induced by focal brain ischemia in rats.
abstract: Spreading depolarization (SD) contributes to the ischemic damage of the penumbra. Although age is the largest predictor of stroke, no studies have examined age dependence of SD appearance. We characterized the electrophysiological and hemodynamic changes in young (6 weeks old, n = 7), middle-aged (9 months old, n = 6), and old (2 years old, n = 7) male Wistar rats during 30 minutes of middle cerebral artery occlusion (MCAO), utilizing multimodal imaging through a closed cranial window over the ischemic cortex: membrane potential changes (with a voltage-sensitive dye), cerebral blood volume (green light reflectance), and cerebral blood flow (CBF, laser-speckle imaging) were observed. The initial CBF drop was similar in all groups, with a significant further reduction during ischemia in old rats (p < 0.01). Age reduced the total number of SDs (p < 0.05) but increased the size of ischemic area displaying prolonged SD (p < 0.01). The growth of area undergoing prolonged SDs positively correlated with the growth of ischemic core area (p < 0.01) during MCAO. Prolonged SDs and associated hypoperfusion likely compromise cortical tissue exposed to even a short focal ischemia in aged rats.
authors.affiliation: Department of Medical Physics and Informatics, School of Medicine, University of Szeged, Szeged, Hungary; Department of Clinical Neurosciences, University of Calgary, Calgary, Canada. Electronic address: dlclark@ualberta.ca.
authors.forename: Darren
authors.initials: D
authors.lastname: Clark
authors.affiliation: Department of Physiology, University of Szeged, Szeged, Hungary.
authors.forename: Ádám
authors.initials: Á
authors.lastname: Institoris
authors.affiliation: Department of Medical Physics and Informatics, School of Medicine, University of Szeged, Szeged, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Kozák
authors.affiliation: Department of Physiology, University of Szeged, Szeged, Hungary.
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Bere
authors.affiliation: Department of Clinical Neurosciences, University of Calgary, Calgary, Canada; Department of Physiology and Pharmacology, University of Calgary, Calgary, Canada; Department of Radiology, University of Calgary, Calgary, Canada.
authors.forename: Ursula
authors.initials: U
authors.lastname: Tuor
authors.affiliation: Department of Medical Physics and Informatics, School of Medicine, University of Szeged, Szeged, Hungary.
authors.forename: Eszter
authors.initials: E
authors.lastname: Farkas
authors.affiliation: Department of Medical Physics and Informatics, School of Medicine, University of Szeged, Szeged, Hungary.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Bari
mesh_terms: D000375:Aging / Q000473:pathology* / Q000502:physiology*; D000818:Animals; D002545:Brain Ischemia / Q000473:pathology* / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology; D002560:Cerebrovascular Circulation; D055724:Electrophysiological Phenomena; D006439:Hemodynamics; D008297:Male; D008564:Membrane Potentials; D017208:Rats, Wistar
keywords: Inverse neurovascular coupling; Middle cerebral artery occlusion; Multimodal imaging; Peri-infarct depolarization; Voltage-sensitive dye