Oxidative and nonoxidative metabolism of excited neurons and astrocytes

Publikation: Bidrag til tidsskriftReviewForskningpeer review

Resumé

There is evidence that the metabolic responses to afferent and efferent nervous activity are dissociated at sites of neuronal excitation in brain. Whether efferent activity follows afferent activity depends on the responsiveness of postsynaptic neurons, which in turn depends on the summation of excitatory and inhibitory postsynaptic potentials. The afferent activity excites the presynaptic terminals and astrocytes, whereas the efferent activity arises from excitation of the dendrites of projection neurons. Measurements in vivo indicate that primary stimulation, elicited by simple stimuli, gives rise to limited increases of energy metabolism associated with afferent activity. Reports show that a major consequence of afferent activity, in addition to the release of excitatory neurotransmitters from presynaptic terminals and the import of glutamate by astrocytes, is the establishment of rates of blood flow commensurate with increased rates of oxidative energy metabolism associated with efferent activity projecting from the site of activation. Increased flow rates overcome the inherent diffusion limitation of oxygen delivery, while increased rates of glycolysis elevate tissue pyruvate contents, to which oxygen consumption rates are matched. In vivo, neurons in the baseline condition sustain no net import of pyruvate or lactate, and the reported changes of metabolism subserving afferent and efferent activity are additive rather than linked by significant additional transfer of pyruvate or lactate from astrocytes. The dissociation of blood flow changes from efferent activity weakens the identification of functional states by changes of blood flow alone. It raises the possibility that uncoupling of flow from oxidative metabolism occurs at sites of low efferent activity, such that dissociations of flow and glycolysis from oxygen consumption signify imbalances of afferent and efferent activity.

OriginalsprogEngelsk
TidsskriftJournal of Cerebral Blood Flow and Metabolism
Vol/bind22
Udgave nummer1
Sider (fra-til)1-14
Antal sider14
ISSN0271-678X
DOI
StatusUdgivet - jan. 2002

Fingeraftryk

Pyruvic Acid
Glycolysis
Neurons
Oxygen Consumption
Energy Metabolism
Lactic Acid
Excitatory Postsynaptic Potentials
Dendrites
Neurotransmitter Agents
Glutamic Acid
Oxygen

Citer dette

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title = "Oxidative and nonoxidative metabolism of excited neurons and astrocytes",
abstract = "There is evidence that the metabolic responses to afferent and efferent nervous activity are dissociated at sites of neuronal excitation in brain. Whether efferent activity follows afferent activity depends on the responsiveness of postsynaptic neurons, which in turn depends on the summation of excitatory and inhibitory postsynaptic potentials. The afferent activity excites the presynaptic terminals and astrocytes, whereas the efferent activity arises from excitation of the dendrites of projection neurons. Measurements in vivo indicate that primary stimulation, elicited by simple stimuli, gives rise to limited increases of energy metabolism associated with afferent activity. Reports show that a major consequence of afferent activity, in addition to the release of excitatory neurotransmitters from presynaptic terminals and the import of glutamate by astrocytes, is the establishment of rates of blood flow commensurate with increased rates of oxidative energy metabolism associated with efferent activity projecting from the site of activation. Increased flow rates overcome the inherent diffusion limitation of oxygen delivery, while increased rates of glycolysis elevate tissue pyruvate contents, to which oxygen consumption rates are matched. In vivo, neurons in the baseline condition sustain no net import of pyruvate or lactate, and the reported changes of metabolism subserving afferent and efferent activity are additive rather than linked by significant additional transfer of pyruvate or lactate from astrocytes. The dissociation of blood flow changes from efferent activity weakens the identification of functional states by changes of blood flow alone. It raises the possibility that uncoupling of flow from oxidative metabolism occurs at sites of low efferent activity, such that dissociations of flow and glycolysis from oxygen consumption signify imbalances of afferent and efferent activity.",
keywords = "Adenosine Triphosphate/metabolism, Animals, Astrocytes/metabolism, Brain/blood supply, Cerebrovascular Circulation, Energy Metabolism, Glucose/metabolism, Glutamic Acid/metabolism, Glycolysis/physiology, Humans, Lactic Acid/metabolism, Neurons/metabolism, Oxidation-Reduction, Oxygen Consumption, Pyruvic Acid/metabolism, Rats, Synaptic Transmission/physiology",
author = "Albert Gjedde and Sean Marrett and Manouchehr Vafaee",
year = "2002",
month = "1",
doi = "10.1097/00004647-200201000-00001",
language = "English",
volume = "22",
pages = "1--14",
journal = "Journal of Cerebral Blood Flow and Metabolism",
issn = "0271-678X",
publisher = "SAGE Publications",
number = "1",

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Oxidative and nonoxidative metabolism of excited neurons and astrocytes. / Gjedde, Albert; Marrett, Sean; Vafaee, Manouchehr.

I: Journal of Cerebral Blood Flow and Metabolism, Bind 22, Nr. 1, 01.2002, s. 1-14.

Publikation: Bidrag til tidsskriftReviewForskningpeer review

TY - JOUR

T1 - Oxidative and nonoxidative metabolism of excited neurons and astrocytes

AU - Gjedde, Albert

AU - Marrett, Sean

AU - Vafaee, Manouchehr

PY - 2002/1

Y1 - 2002/1

N2 - There is evidence that the metabolic responses to afferent and efferent nervous activity are dissociated at sites of neuronal excitation in brain. Whether efferent activity follows afferent activity depends on the responsiveness of postsynaptic neurons, which in turn depends on the summation of excitatory and inhibitory postsynaptic potentials. The afferent activity excites the presynaptic terminals and astrocytes, whereas the efferent activity arises from excitation of the dendrites of projection neurons. Measurements in vivo indicate that primary stimulation, elicited by simple stimuli, gives rise to limited increases of energy metabolism associated with afferent activity. Reports show that a major consequence of afferent activity, in addition to the release of excitatory neurotransmitters from presynaptic terminals and the import of glutamate by astrocytes, is the establishment of rates of blood flow commensurate with increased rates of oxidative energy metabolism associated with efferent activity projecting from the site of activation. Increased flow rates overcome the inherent diffusion limitation of oxygen delivery, while increased rates of glycolysis elevate tissue pyruvate contents, to which oxygen consumption rates are matched. In vivo, neurons in the baseline condition sustain no net import of pyruvate or lactate, and the reported changes of metabolism subserving afferent and efferent activity are additive rather than linked by significant additional transfer of pyruvate or lactate from astrocytes. The dissociation of blood flow changes from efferent activity weakens the identification of functional states by changes of blood flow alone. It raises the possibility that uncoupling of flow from oxidative metabolism occurs at sites of low efferent activity, such that dissociations of flow and glycolysis from oxygen consumption signify imbalances of afferent and efferent activity.

AB - There is evidence that the metabolic responses to afferent and efferent nervous activity are dissociated at sites of neuronal excitation in brain. Whether efferent activity follows afferent activity depends on the responsiveness of postsynaptic neurons, which in turn depends on the summation of excitatory and inhibitory postsynaptic potentials. The afferent activity excites the presynaptic terminals and astrocytes, whereas the efferent activity arises from excitation of the dendrites of projection neurons. Measurements in vivo indicate that primary stimulation, elicited by simple stimuli, gives rise to limited increases of energy metabolism associated with afferent activity. Reports show that a major consequence of afferent activity, in addition to the release of excitatory neurotransmitters from presynaptic terminals and the import of glutamate by astrocytes, is the establishment of rates of blood flow commensurate with increased rates of oxidative energy metabolism associated with efferent activity projecting from the site of activation. Increased flow rates overcome the inherent diffusion limitation of oxygen delivery, while increased rates of glycolysis elevate tissue pyruvate contents, to which oxygen consumption rates are matched. In vivo, neurons in the baseline condition sustain no net import of pyruvate or lactate, and the reported changes of metabolism subserving afferent and efferent activity are additive rather than linked by significant additional transfer of pyruvate or lactate from astrocytes. The dissociation of blood flow changes from efferent activity weakens the identification of functional states by changes of blood flow alone. It raises the possibility that uncoupling of flow from oxidative metabolism occurs at sites of low efferent activity, such that dissociations of flow and glycolysis from oxygen consumption signify imbalances of afferent and efferent activity.

KW - Adenosine Triphosphate/metabolism

KW - Animals

KW - Astrocytes/metabolism

KW - Brain/blood supply

KW - Cerebrovascular Circulation

KW - Energy Metabolism

KW - Glucose/metabolism

KW - Glutamic Acid/metabolism

KW - Glycolysis/physiology

KW - Humans

KW - Lactic Acid/metabolism

KW - Neurons/metabolism

KW - Oxidation-Reduction

KW - Oxygen Consumption

KW - Pyruvic Acid/metabolism

KW - Rats

KW - Synaptic Transmission/physiology

U2 - 10.1097/00004647-200201000-00001

DO - 10.1097/00004647-200201000-00001

M3 - Review

VL - 22

SP - 1

EP - 14

JO - Journal of Cerebral Blood Flow and Metabolism

JF - Journal of Cerebral Blood Flow and Metabolism

SN - 0271-678X

IS - 1

ER -