Cerebral Metabolism during Propofol Anesthesia in Humans Studied with Positron Emission Tomography

Alkire, Michael T.; Haier, Richard J.; Barker, Steven J.; Shah, Nitin; Wu, Joseph C.; Kao, James Y.

doi:10.1097/00000542-199502000-00010

Cited by 291 publications

(165 citation statements)

References 23 publications

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“…Finally, given the importance of ubiquitously high oxidative energy demand for supporting conscious human behavior, 63 we propose that clinical fMRI studies could take advantage of quantitative measures of metabolic energy when evaluating patients. [70][71][72][73][74] Reproduced with permission from Clin Pharmacol Ther. 72 (B) Non-REM sleep shows CMR glc in the visual cortex to be reduced to 0.26±0.06 mmol/g per minute from 0.33±0.07 mmol/g per minute in the awake brain.…”

Section: Discussionmentioning

confidence: 99%

Glutamatergic Function in the Resting Awake Human Brain is Supported by Uniformly High Oxidative Energy

Hyder

Fulbright

Shulman

et al. 2013

J Cereb Blood Flow Metab

107

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Rodent 13 C magnetic resonance spectroscopy studies show that glutamatergic signaling requires high oxidative energy in the awake resting state and allowed calibration of functional magnetic resonance imaging (fMRI) signal in terms of energy relative to the resting energy. Here, we derived energy used for glutamatergic signaling in the awake resting human. We analyzed human data of electroencephalography (EEG), positron emission tomography (PET) maps of oxygen (CMR O2 ) and glucose (CMR glc ) utilization, and calibrated fMRI from a variety of experimental conditions. CMR glc and EEG in the visual cortex were tightly coupled over several conditions, showing that the oxidative demand for signaling was four times greater than the demand for nonsignaling events in the awake state. Variations of CMR O2 and CMR glc from gray-matter regions and networks were within ±10% of means, suggesting that most areas required similar energy for ubiquitously high resting activity. Human calibrated fMRI results suggest that changes of fMRI signal in cognitive studies contribute at most ± 10% CMR O2 changes from rest. The PET data of sleep, vegetative state, and anesthesia show metabolic reductions from rest, uniformly 420% across, indicating no region is selectively reduced when consciousness is lost. Future clinical investigations will benefit from using quantitative metabolic measures. Keywords: astrocytes; baseline; field potentials; glutamate; multiunit activity; resting state INTRODUCTIONThe human brain consumes 20% of the body's energy at rest despite being only 2% of total body mass. 1 Normally glucose oxidation is the source of energy production supporting brain function 2 in which gray-matter signaling (i.e., events associated with neuronal firing) is dominated by glutamatergic neurons. 3 Estimates of the fraction of resting brain energy devoted to signaling were originally quite low. 4 But recent experimental studies in rodents and theoretical modeling have converged on the conclusion that majority of the resting energy consumption supports glutamatergic signaling and the energy demand changes linearly with pyramidal neuron firing rates and glutamate neurotransmitter release and reuptake. [5][6][7][8][9] Therefore in rodent models it is possible, to a first order, to show that the resting energy is primarily dedicated to total glutamatergic signaling, and the changes in neuronal signaling relative to a well-defined resting activity level can be used to calibrate changes in energy consumption during functional magnetic resonance imaging (fMRI) experiments. 10,11 In the awake human brain, however, the fraction of resting energy usage devoted to glutamatergic signaling is less well understood. The magnitude of neuronal signaling in the human brain, and by inference the commensurate energy demand, underscores the functional relevance of resting activity and has profound implications for interpreting fMRI experiments in humans. [12][13][14] Given the rapidly increasing use of resting-state fMRI in mapping networks-defined as a...

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Section: Discussionmentioning

confidence: 99%

Glutamatergic Function in the Resting Awake Human Brain is Supported by Uniformly High Oxidative Energy

Hyder

Fulbright

Shulman

et al. 2013

J Cereb Blood Flow Metab

107

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“…Propofol also decreases the cerebral metabolic rate of O 2 (Enlund et al, 1997) and cerebral metabolism (Alkire et al, 1995;Dam et al, 1990). However, it does not accumulate and this facilitates long term use (Hedenquist, Hellebrkers, 2003) and places it as the drug of choice for prospective animal fMRI studies.…”

Section: Discussionmentioning

confidence: 99%

Propofol allows precise quantitative arterial spin labelling functional magnetic resonance imaging in the rat

et al. 2010

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M., Propofol allows precise quantitative arterial spin labelling functional magnetic resonance imaging in the rat, NeuroImage (2010), doi: 10.1016/j.neuroimage. 2010.03.024 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

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“…When different anesthetics are titrated to the point of unresponsiveness, the resulting reduction in CMRGlu is nearly as low as that observed in VS patients. [18][19][20] During propofol anesthesia, brain metabolism sometimes decreases to 30 percent of normal values. Another example of transient metabolic depression has been observed by our own and other centers during slow-wave sleep.…”

Section: Global Impairment In Cerebral Metab Olismmentioning

confidence: 99%

Brain Function in the Vegetative State

Laureys

Antoine

Boly

et al. 2004

Advances in Experimental Medicine and Biology

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Cerebral Metabolism during Propofol Anesthesia in Humans Studied with Positron Emission Tomography

Cited by 291 publications

References 23 publications

Glutamatergic Function in the Resting Awake Human Brain is Supported by Uniformly High Oxidative Energy

Glutamatergic Function in the Resting Awake Human Brain is Supported by Uniformly High Oxidative Energy

Propofol allows precise quantitative arterial spin labelling functional magnetic resonance imaging in the rat

Brain Function in the Vegetative State

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