Information in the introduction is from the  following review articles, as well as from the references cited in the other sections.

Ebrahim IO, Howard RS, Kopelman MD, Sharief MK, Williams AJ. The hypocretin/orexin system. J R Soc Med 95: 227-230 (2002).  [This article mainly discusses narcolepsy]

Siegel JM. Hypocretin (orexin): role in normal behavior and neuropathology. Ann. Rev. Psychol. 55: 125-148 (2004). doi: 10.1146/annurev.psych.55.090902.141545. [Lots of stuff on arousal effects, including some mechanism, as well as some information from own experiments.  Does not believe that effects on appetite are important in normal animals.]

Willie JT, Chemelli RM, Sinton CM, Yanagisawa M. To eat or to sleep? Orexin in the regulation of feeding and wakefulness.  Annu. Rev. Neurosci. 24:429-58 (2001).  [Good overall review. I think this was also posted on wikispaces-- ?]


Images: from wikipedia-- able to be freely copied and distributed according to their liscensing agreements.

1. Ohkubo T, Boswell T, Lumineau S. Molecular cloning of chicken prepro-orexin cDNA and preferential expression in the chicken hypothalamus. Biochimica et Biophysica Acta 1577: 476-480 (2002). 

2. Nakamachi T, Matsuda K, Maruyama K, Miura T, Uchiyama M, Funahashi H, Sakurai T, Shioda S. Regulation by orexin of feeding behaviour and locomotor activity in the goldfish. Journal of Neuroendocrinology 18(4): 290-297 (2006).

3. Faraco JH, Appelbaum L, Marin W, Gaus SE, Mourrain P, Mignot E. Regulation of hypocretin (orexin) expression in embryonic zebrafish. Journal of Biological Chemistry 281(40): 29753-29761 (2006).

4. Singletary KG, Delville Y, Farrell WJ, Wilczynski W. Distribution of orexin/hypocretin immunoreactivity in the nervous system of the green Treefrog, Hyla cinerea. Brain Research 1041: 231-236 (2005).

5. Farrell WJ, Delville Y, Wilczynski W. Immunocytochemical localization of orexin in the brain of the green anole lizard (anolis carolinensis).  Meeting Abstract.  Society for Neuroscience Abstracts 33: 828.4 (2003).

6. Eiland MM, Thiannical T, Siegel JM. Distribution of hypocretin (orexin) and MCH containing cells in the turtle. Meeting Abstract. Society for Neuroscience Abstracts 27(1): 1088 (2001).  


1. Yamamoto Y, Ueta Y, Hara Y, Serino R, Nomura M, Shibuya I, Shirahata A, Yamashita H. Postnatal development of orexin/hypocretin in rats. Molecular Brain Research 78(1-2): 108-119. doi:10.1016/S0169-328X(00)00080-2

2.  Kanenishi K, Ueno M, Momose S, Kuwabara H, Tanaka H, Sato C, Kobayashi T, Hino O, Sakamoto H, Hata T.  Prepro-orexin mRNA expression in the rat brain is increased during pregnancy. Neuroscience Letters 368(1): 73-77 (2004).

3. Steininger TL, Kilduff TS, Behan M, Benca RM, Landry CF. Comparison of hypocretin/orexin and melanin-concentrating hormone neurons and axonal projections in the embryonic and postnatal rat brain. J Chem Neuroanat 27(3):165-81 (2004).


1. Huang ZL, Qu WM, Li WD, Mochizuki T, Eguchi N, Watanabe T, Urade Y, Hayaishi O. Arousal effect of orexin A depends on activation of the histaminergic system.  PNAS 98(17): 9965- 9970 (2001). doi: 10.1073pnas.181330998

2. Harris GC, Wimmer M, Aston-Jones G. A role for lateral hypothalamic orexin neurons in reward seeking. Nature 437: 556-559 (2005).  doi:10.1038/nature04071.

3. Siegel JM. Hypocretin (orexin): role in normal behavior and neuropathology. Ann. Rev. Psychol. 55: 125-148 (2004). doi: 10.1146/annurev.psych.55.090902.141545.

4. Sweet DC, Levine AS, Billington CJ, Kotz CM. Feeding response to central orexins. Brain Research 821: 535-538 (1999).