title: Distinct effects of isoflurane on basal BOLD signals in tissue/vascular microstructures in rats.
abstract: Isoflurane is a well-known volatile anesthetic. However, it remains equivocal whether its effects on BOLD signal differ depending on the types of intracranial structures, such as capillaries and large blood vessels. We compared dose-dependent effect of isoflurane on the basal BOLD signals in distinct cerebral structures (tissue structure or large vessels) using high resolution T2*-images at 9.4 T MRI system in rat somatosensory cortex. The local field potential (LFP) in the somatosensory cortex and mean arterial pressure (MAP) were also investigated. Isoflurane induced inverted U-shaped dose-dependent change in BOLD signal in large vessels and tissue regions: BOLD signal under 2.0% and 2.5% isoflurane significantly increased from the maintenance dose (1.5%) and that under 3.0% was similar to maintenance dose. Remarkably, BOLD signal increase in tissue regions under 2.5% was significantly smaller than that in large vessels. The MAP decreased monotonically due to the dose of isoflurane and the LFP was strongly suppressed under high dose (2.5% and 3.0%). These results indicate that isoflurane-induced alteration of MAP and neuronal activity affected BOLD signal and, especially, BOLD signal in the tissue regions was more affected by the neuronal activity.
authors.affiliation: Department of Neuroscience, The Jikei University School of Medicine, 3-25-8, Minato-ku, Tokyo 105-8461, Japan.|Neurospin, Commissariat à l'Energie Atomique et aux Energies Alternatives, Bat 145, Point Courrier 156, Gif-sur-Yvette 91191, France.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Tsurugizawa
authors.affiliation: Department of Neuroscience, The Jikei University School of Medicine, 3-25-8, Minato-ku, Tokyo 105-8461, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Neuroscience, The Jikei University School of Medicine, 3-25-8, Minato-ku, Tokyo 105-8461, Japan.
authors.forename: Fusao
authors.initials: F
authors.lastname: Kato
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002533:Cerebral Angiography; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D007530:Isoflurane / Q000494:pharmacology*; D018810:Magnetic Resonance Angiography; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000098:blood supply / Q000000981:diagnostic imaging
chemical_list: D007530:Isoflurane