In:
PLOS Biology, Public Library of Science (PLoS), Vol. 20, No. 10 ( 2022-10-27), p. e3001440-
Abstract:
The cerebral cortex is organized in cortical layers that differ in their cellular density, composition, and wiring. Cortical laminar architecture is also readily revealed by staining for cytochrome oxidase—the last enzyme in the respiratory electron transport chain located in the inner mitochondrial membrane. It has been hypothesized that a high-density band of cytochrome oxidase in cortical layer IV reflects higher oxygen consumption under baseline (unstimulated) conditions. Here, we tested the above hypothesis using direct measurements of the partial pressure of O 2 (pO 2 ) in cortical tissue by means of 2-photon phosphorescence lifetime microscopy (2PLM). We revisited our previously developed method for extraction of the cerebral metabolic rate of O 2 (CMRO 2 ) based on 2-photon pO 2 measurements around diving arterioles and applied this method to estimate baseline CMRO 2 in awake mice across cortical layers. To our surprise, our results revealed a decrease in baseline CMRO 2 from layer I to layer IV. This decrease of CMRO 2 with cortical depth was paralleled by an increase in tissue oxygenation. Higher baseline oxygenation and cytochrome density in layer IV may serve as an O 2 reserve during surges of neuronal activity or certain metabolically active brain states rather than reflecting baseline energy needs. Our study provides to our knowledge the first quantification of microscopically resolved CMRO 2 across cortical layers as a step towards better understanding of brain energy metabolism.
Type of Medium:
Online Resource
ISSN:
1545-7885
DOI:
10.1371/journal.pbio.3001440
DOI:
10.1371/journal.pbio.3001440.g001
DOI:
10.1371/journal.pbio.3001440.g002
DOI:
10.1371/journal.pbio.3001440.g003
DOI:
10.1371/journal.pbio.3001440.s001
DOI:
10.1371/journal.pbio.3001440.s002
DOI:
10.1371/journal.pbio.3001440.s003
DOI:
10.1371/journal.pbio.3001440.s004
DOI:
10.1371/journal.pbio.3001440.s005
DOI:
10.1371/journal.pbio.3001440.s006
DOI:
10.1371/journal.pbio.3001440.s007
DOI:
10.1371/journal.pbio.3001440.s008
DOI:
10.1371/journal.pbio.3001440.s009
DOI:
10.1371/journal.pbio.3001440.s010
DOI:
10.1371/journal.pbio.3001440.s011
DOI:
10.1371/journal.pbio.3001440.s012
DOI:
10.1371/journal.pbio.3001440.s013
DOI:
10.1371/journal.pbio.3001440.r001
DOI:
10.1371/journal.pbio.3001440.r002
DOI:
10.1371/journal.pbio.3001440.r003
DOI:
10.1371/journal.pbio.3001440.r004
DOI:
10.1371/journal.pbio.3001440.r005
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2022
detail.hit.zdb_id:
2126773-X
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