The Cerebral Metabolic Effects of Isoflurane at and above Concentrations that Suppress Cortical Electrical Activity

Newberg, Leslie A.; Milde, James H.; Michenfelder, John D.

doi:10.1097/00000542-198307000-00005

Cited by 202 publications

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“…Likewise, virtual isoelectricity was seen at around 2 MAC isoflurane in dogs (Newberg et al. ). In chickens, burst suppression increased in a dose‐dependent manner for both isoflurane and sevoflurane.…”

Section: Discussionmentioning

confidence: 91%

Effects of isoflurane, sevoflurane and methoxyflurane on the electroencephalogram of the chicken

McIlhone

Beausoleil

Johnson

et al. 2014

Veterinary Anaesthesia and Analgesia

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Section: Discussionmentioning

confidence: 91%

Effects of isoflurane, sevoflurane and methoxyflurane on the electroencephalogram of the chicken

McIlhone

Beausoleil

Johnson

et al. 2014

Veterinary Anaesthesia and Analgesia

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“…Even long‐term exposure to high concentrations of isoflurane did not reduce cerebral ATP levels as reported in a previous study (Newberg et al . ). Therefore, the reduced ATP levels in the microwaved brains presented here were likely because of microwave effects and not anesthesia.…”

Section: Discussionmentioning

confidence: 97%

Microwave irradiation decreases ATP, increases free [Mg²⁺], and alters in vivo intracellular reactions in rat brain

Srivastava

Kashiwaya

Chen

et al. 2012

Journal of Neurochemistry

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Rapid inactivation of metabolism is essential for accurately determining the concentrations of metabolic intermediates in the in vivo state. We compared a broad spectrum of energetic intermediate metabolites and neurotransmitters in brains obtained by microwave irradiation to those obtained by freeze blowing, the most rapid method of extracting and freezing rat brain. The concentrations of many intermediates, cytosolic free NAD(P)+/NAD(P)H ratios, as well as neurotransmitters were not affected by the microwave procedure. However, the brain concentrations of ATP were about 30% lower, whereas those of ADP, AMP, and GDP were higher in the microwave-irradiated compared with the freeze-blown brains. In addition, the hydrolysis of approximately 1 μmol/g of ATP, a major in vivo Mg2+-binding site, was related to approximately five-fold increase in free [Mg2+] (0.53 ± 0.07 mM in freeze blown vs. 2.91 mM ± 0.48 mM in microwaved brains), as determined from the ratio [citrate]/[isocitrate]. Consequently, many intracellular properties, such as the phosphorylation potential and the ΔG’ of ATP hydrolysis were significantly altered in microwaved tissue. The determinations of some glycolytic and TCA cycle metabolites, the phosphorylation potential, and the ΔG’ of ATP hydrolysis do not represent the in vivo state when using microwave-fixed brain tissue.

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“…Higher dose (1–2 minimum alveolar concentration (MAC)) of isoflurane not only increases the rCBF and rCBV1718 but also decreases the CMRO 2 in the cerebral cortex19 dose-dependently. The MAP is also decreased by isoflurane dose-dependently, but the partial pressure of oxygen (pO 2 ), partial pressure of carbon dioxide (pCO 2 ) and pH are constant1720, consistent with our result.…”

Section: Discussionmentioning

confidence: 99%

Distinct effects of isoflurane on basal BOLD signals in tissue/vascular microstructures in rats

Tsurugizawa

Takahashi

Kato

2016

Sci Rep

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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.

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The Cerebral Metabolic Effects of Isoflurane at and above Concentrations that Suppress Cortical Electrical Activity

Cited by 202 publications

References 0 publications

Effects of isoflurane, sevoflurane and methoxyflurane on the electroencephalogram of the chicken

Effects of isoflurane, sevoflurane and methoxyflurane on the electroencephalogram of the chicken

Microwave irradiation decreases ATP, increases free [Mg²⁺], and alters in vivo intracellular reactions in rat brain

Distinct effects of isoflurane on basal BOLD signals in tissue/vascular microstructures in rats

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The Cerebral Metabolic Effects of Isoflurane at and above Concentrations that Suppress Cortical Electrical Activity

Cited by 202 publications

References 0 publications

Effects of isoflurane, sevoflurane and methoxyflurane on the electroencephalogram of the chicken

Effects of isoflurane, sevoflurane and methoxyflurane on the electroencephalogram of the chicken

Microwave irradiation decreases ATP, increases free [Mg2+], and alters in vivo intracellular reactions in rat brain

Distinct effects of isoflurane on basal BOLD signals in tissue/vascular microstructures in rats

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Microwave irradiation decreases ATP, increases free [Mg²⁺], and alters in vivo intracellular reactions in rat brain