Pharmacogenetic modulation of orexin neurons alters sleep/wakefulness states in mice

PLoS One. 2011;6(5):e20360. doi: 10.1371/journal.pone.0020360. Epub 2011 May 27.


Hypothalamic neurons expressing neuropeptide orexins are critically involved in the control of sleep and wakefulness. Although the activity of orexin neurons is thought to be influenced by various neuronal input as well as humoral factors, the direct consequences of changes in the activity of these neurons in an intact animal are largely unknown. We therefore examined the effects of orexin neuron-specific pharmacogenetic modulation in vivo by a new method called the Designer Receptors Exclusively Activated by Designer Drugs approach (DREADD). Using this system, we successfully activated and suppressed orexin neurons as measured by Fos staining. EEG and EMG recordings suggested that excitation of orexin neurons significantly increased the amount of time spent in wakefulness and decreased both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep times. Inhibition of orexin neurons decreased wakefulness time and increased NREM sleep time. These findings clearly show that changes in the activity of orexin neurons can alter the behavioral state of animals and also validate this novel approach for manipulating neuronal activity in awake, freely-moving animals.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal / drug effects
  • Blood-Brain Barrier / drug effects
  • Blood-Brain Barrier / metabolism
  • Calcium / metabolism
  • Channelrhodopsins
  • Clozapine / administration & dosage
  • Clozapine / analogs & derivatives
  • Clozapine / metabolism
  • Clozapine / pharmacology
  • Dependovirus / genetics
  • Humans
  • Injections, Intraperitoneal
  • Integrases / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Male
  • Mice
  • Mice, Transgenic
  • Molecular Imaging
  • Neurons / drug effects
  • Neurons / metabolism*
  • Neuropeptides / metabolism*
  • Optical Phenomena
  • Orexins
  • Pharmacogenetics / methods*
  • Receptor, Muscarinic M3 / genetics
  • Receptor, Muscarinic M3 / metabolism
  • Receptor, Muscarinic M4 / genetics
  • Receptor, Muscarinic M4 / metabolism
  • Sleep / drug effects*
  • Sleep / genetics*
  • Wakefulness / drug effects*
  • Wakefulness / genetics*


  • Channelrhodopsins
  • Intracellular Signaling Peptides and Proteins
  • Neuropeptides
  • Orexins
  • Receptor, Muscarinic M3
  • Receptor, Muscarinic M4
  • Cre recombinase
  • Integrases
  • Clozapine
  • clozapine N-oxide
  • Calcium