Biochemistry and the Central Nervous System

McIlwain, H.

doi:10.1097/00005053-195511000-00018

Cited by 128 publications

(99 citation statements)

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“…As hexokinase can phosphorylate fructose to fructose-6-phosphate, as well as glucose to glucose-6-phosphate, we determined the relationship between fructose concentrations and hexokinase activity and found the K m increased to 1.907 0.45 mmol/L with a V max of 392.6713.6 nmol/min per mg protein (n = 3; Figure 5B). This increase in the K m of hexokinase with fructose as substrate has been reported previously (McIlwain and Bachelard, 1985;Newsholme and Leech, 1983;Sols and Crane, 1954). We next sought to determine if there was any fructokinase activity in the brain.…”

Section: Hexokinase and Fructokinase Activitysupporting

confidence: 87%

Section: Hexokinase and Fructokinase Activitymentioning

confidence: 99%

“…Hexokinase assays of brain (occipital cortex) were performed for the sake of comparison, as the kinetic parameters of brain hexokinase are well established (McIlwain and Bachelard, 1985). The concentration dependence of brain hexokinase with glucose as substrate yielded a K m of 31.571.5 mmol/L and a V max of 344.77 17.5 nmol/min per mg protein (n = 3; Figure 5A), which is consistent with previously published results (McIlwain and Bachelard, 1985;Newsholme and Leech, 1983). As hexokinase can phosphorylate fructose to fructose-6-phosphate, as well as glucose to glucose-6-phosphate, we determined the relationship between fructose concentrations and hexokinase activity and found the K m increased to 1.907 0.45 mmol/L with a V max of 392.6713.6 nmol/min per mg protein (n = 3; Figure 5B).…”

Section: Hexokinase and Fructokinase Activitymentioning

confidence: 99%

“…Although it is widely agreed that glucose is the main energy substrate of the adult mammalian brain under resting conditions (McIlwain and Bachelard, 1985), it has been known for over half a century, however, that in vitro brain preparations can survive on nonglucose substrates in the total absence of exogenously applied glucose (McIlwain, 1953). This implies that it is the limiting permeability of the blood-brain barrier, rather than the brain's inability to metabolise substrates, that restricts the metabolic substrates the brain uses.…”

Section: Introductionmentioning

confidence: 99%

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Fructose Metabolism in the Adult Mouse Optic Nerve, A Central White Matter Tract

Fowler

Rathbone

Allen

et al. 2006

J Cereb Blood Flow Metab

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Our recent report that fructose supported the metabolism of some, but not all axons, in the adult mouse optic nerve prompted us to investigate in detail fructose metabolism in this tissue, a typical central white matter tract, as these data imply efficient fructose metabolism in the central nervous system (CNS). In artificial cerebrospinal fluid containing 10 mmol/L glucose or 20 mmol/L fructose, the stimulus-evoked compound action potential (CAP) recorded from the optic nerve consisted of three stable peaks. Replacing 10 mmol/L glucose with 10 mmol/L fructose, however, caused delayed loss of the 1st CAP peak (the 2nd and 3rd CAP peaks were unaffected). Glycogen-derived metabolic substrate(s) temporarily sustained the 1st CAP peak in 10 mmol/L fructose, as depletion of tissue glycogen by a prior period of aglycaemia or high-frequency CAP discharge rendered fructose incapable of supporting the 1st CAP peak. Enzyme assays showed the presence of both hexokinase and fructokinase (both of which can phosphorylate fructose) in the optic nerve. In contrast, only hexokinase was expressed in cerebral cortex. Hexokinase in optic nerve had low affinity and low capacity with fructose as substrate, whereas fructokinase displayed high affinity and high capacity for fructose. These findings suggest an explanation for the curious fact that the fast conducting axons comprising the 1st peak of the CAP are not supported in 10 mmol/L fructose medium; these axons probably do not express fructokinase, a requirement for efficient fructose metabolism.

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Section: Hexokinase and Fructokinase Activitysupporting

confidence: 87%

Section: Hexokinase and Fructokinase Activitymentioning

confidence: 99%

Section: Hexokinase and Fructokinase Activitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fructose Metabolism in the Adult Mouse Optic Nerve, A Central White Matter Tract

Fowler

Rathbone

Allen

et al. 2006

J Cereb Blood Flow Metab

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“…For example using techniques as detailed here, we have successfully made multiplexed measurements for eight cytokines from as few as 100 CA3 pyramidal neurons obtained via laser microscope dissection (Kraig et al, 2002). Brain gray matter contains 83% water, 7.5% protein, 1% RNA, 0.25% DNA and 6% lipids (McIlwain and Bachelard, 1971). Since, a single cell contains about 20 pg of RNA (Schober et al, 2001), 100 CA3 pyramidal cells contain about 15 ng of total protein.…”

Section: Advantages Of Multiplexed Bead-based Immunoassays For Proteimentioning

confidence: 99%

Optimization of multiplexed bead-based cytokine immunoassays for rat serum and brain tissue

Hulse

Kunkler

Fedynyshyn

et al. 2004

Journal of Neuroscience Methods

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The ability to simultaneously quantify multiple signaling molecule protein levels from microscopic neural tissue samples would be of great benefit to deciphering how they affect brain function. This follows from evidence that indicates signaling molecules can be pleiotropic and can have complex interactive behavior that is regionally and cellularly heterogeneous. Multiplexed examination of tissue proteins has been exceedingly difficult because of the absence of available techniques. This void now has been removed by the commercial availability of bead-based immunoassays for targeted proteins that allow analyses of up to 100 (6-150 kDa) proteins from as little as 12 μl. Thus far used only for sera (human and mouse) and culture media, we demonstrate here that sensitive (as low as 2 pg/ml), wide-ranging (up to 2-32 000 pg/ml), accurate (8% intra-assay covariance) and reliable (4-7% inter-assay covariance) measurements can be made of nine exemplary cytokines (e.g., IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-γ, TNF-α) simultaneously not only from rat serum but, for the first time, also brain tissue. Furthermore, we describe animal handling procedures that minimize stress as determined by serum glucocorticoid levels since they can influence cytokine expression.

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Control of Rate of Intracellular Respiration

Slater

Hülsmann

1959

Ciba Foundation Symposium — Regulation of Cell Metabolism

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Biochemistry and the Central Nervous System

Cited by 128 publications

References 0 publications

Fructose Metabolism in the Adult Mouse Optic Nerve, A Central White Matter Tract

Fructose Metabolism in the Adult Mouse Optic Nerve, A Central White Matter Tract

Optimization of multiplexed bead-based cytokine immunoassays for rat serum and brain tissue

Control of Rate of Intracellular Respiration

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