Orexin neurons

Orexin neurons, likely to be glutamatergic themselves, express the excitatory amino acid transporter EAAT3, vesicular glutamate transporters VGLUT1 and VGLUT2, secretogranin II, ionotropic (NMDAR,... 

Mileykovskiy, B. Y., Kiyashchenko, L. I. Siegel, J. M. (2005). Behavioral correlates of activity in identified hypocrethi/orexin neurons. Neuron 46, 787-98. 

Yamanaka A., Muraki Y., Ichiki K el al. (2006). Orexin neurons are directly and indirectly regulated by catecholamines in a complex manner. J. Neurophysiol. Epub-ahead of print. 

Grivel, J., Cvetkovic, V., Bayer, L. el al. (2005). The wake-promoting hypocretin/orexin neurons change their response to noradrenaline after sleep deprivation. J. Neurosci 25, 4127-30. 

Selective postnatal degeneration of orexin neurons, complete by early adulthood Selective postnatal degeneration of orexin neurons, complete by early adulthood... 

Although human narcolepsy is not typically associated with orexin gene mutations, the orexin / model is most similar to the case of a narcoleptic-cataplectic child, severely symptomatic from infancy, who has a genetic defect in orexin production and release (Peyron et al., 2000). Thus, constitutive orexin deficiency alone in the presence of otherwise histologically normal orexin neurons... 

Significantly, orexin/ataxin-3 mice respond to intracerebroventricular injection of orexin-A with increased wakefulness and suppression of REM sleep and cataplexy. This pharmacological reversal indicated that orexin receptors remain functional in the absence of orexin neurons, and that these narcoleptic mice can respond to orexin agonists, a finding with significant therapeutic implications (Mieda et al., 2004b). 

Orexin neurons innervate all the major brain regions implicated in the generation of wakefulness including the aminergic and cholinergic brainstem... 

Beuckmann, C. T., Sinton, C. M., Williams, S. C. et al. (2004). Expression of a poly-glutamine-ataxin-3 transgene in orexin neurons induces narcolepsy-cataplexy in the rat. J. Neurosci 24, 4469-77. 

Burdakov, D., Gerasimenko, 0. Verkhratsky, A. (2005). Physiological changes in glucose differentially modulate the excitability of hypothalamic melaninconcentrating hormone and orexin neurons in situ. J. Neurosci. 25,... 

Hara, J., Beuckmann, C. T., Nambu, T. et al. (2001). Genetic ablation of orexin neurons in mice results in narcolepsy, hypophagia, and obesity. Neuron 30, 345-54. 

Mieda, M., Willie, J. T., Hara, J. et al (2004b). Orexin peptides prevent cataplexy and improve wakefulness in an orexin neuron-ablated model of narcolepsy in mice. Proc. Natl. Acad. Scl USA 101, 4649-54. 

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