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Scientific article
English

Exclusive postsynaptic action of hypocretin-orexin on sublayer 6b cortical neurons

Contributors

Bayer, Laurence; Serafin, Mauro; Eggermann, Emmanuel; Saint-Mleux, Benoit; Machard, Daniele; Jones, B. E.; Muhlethaler, Michel

Published in

The Journal of neuroscience, vol. 24, no. 30, p. 6760-6764

Publication date

2004

Abstract

The hypocretin-orexin (hcrt-orx) neurons are thought to maintain wakefulness because their loss results in narcolepsy. This role may be fulfilled by the excitatory action that the hcrt-orx peptide exerts on multiple brainstem and forebrain systems that, in turn, promote cortical activation. Here, we examined whether hcrt-orx may also exert a postsynaptic excitatory action at the level of the cortex, where hcrt-orx fibers project. However, we found that neurons in layers 2-5 in the primary somatosensory cortex (SSp) were unresponsive to hcrt-orx. We then found that although all neurons tested in sublayer 6a were also unresponsive to hcrt-oxr, all those tested in sublayer 6b were highly sensitive to the peptide. The sublayer selectivity of hcrt-oxr was not restricted to the somatosensory cortex, because it was also found to be present in the primary visual cortex, the motor cortex, and the cingulate cortex. In the SSp, in which the hcrt-oxr effect was investigated further, it was demonstrated to be postsynaptic, to result from an interaction with Hcrtr2-OX2 receptors and to depend on the closure of a potassium conductance. Similar to the selectivity of action in the thalamus, where hcrt-oxr excites the nonspecific thalamocortical projection neurons and not the specific sensory relay neurons, here in the cortex, it excites a specific subset of cortical neurons which, through corticocortical projections, may also be involved in promoting widespread cortical activation.

Keywords

  • Animals
  • Arousal/ drug effects/physiology
  • Cerebral Cortex/cytology/ drug effects/physiology
  • Gyrus Cinguli/cytology/drug effects/physiology
  • Intracellular Signaling Peptides and Proteins/ pharmacology
  • Ion Channels/physiology
  • Motor Cortex/cytology/drug effects/physiology
  • Neural Pathways/drug effects
  • Neurons/classification/ drug effects/physiology
  • Neuropeptides/ pharmacology
  • Patch-Clamp Techniques
  • Potassium/physiology
  • Rats
  • Receptors, G-Protein-Coupled
  • Receptors, Neuropeptide/ drug effects/physiology
  • Somatosensory Cortex/cytology/drug effects/physiology
  • Synaptic Transmission/drug effects
  • Visual Cortex/cytology/drug effects/physiology
  • Wakefulness/drug effects/physiology

UNIGE affiliation entities

Citation (ISO format)

BAYER, Laurence et al. Exclusive postsynaptic action of hypocretin-orexin on sublayer 6b cortical neurons. In: The Journal of neuroscience, 2004, vol. 24, n° 30, p. 6760–6764. doi: 10.1523/JNEUROSCI.1783-04.2004

Main files (1)

Article

Identifiers

Additional URL for this publication

http://www.jneurosci.org/cgi/reprint/24/30/6760.pdf

Journal ISSN

0270-6474
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Technical informations

Creation

06/08/2010 13:46:00

First validation

06/08/2010 13:46:00

Update

14/03/2023 15:57:50

Status update

14/03/2023 15:57:50

Last indexation

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