Nucleus raphe obscurus

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Nucleus raphe obscurus
Section of the medulla oblongata at about the middle of the olive. (Raphe nuclei not labeled, but 'raphe' labeled at left.)
Latin nucleus raphes obscurus
MeSH D065849
NeuroNames 740
NeuroLex ID birnlex_1369
TA A14.1.04.319
FMA 72585
Anatomical terms of neuroanatomy

The nucleus raphe obscurus, despite the implications of its name, has some very specific functions and connections of afferent and efferent nature. The nucleus raphes obscurus projects to the cerebellar lobes VI and VII and to crus II along with the nucleus raphe pontis.[1]

The nucleus raphes obscurus has also been implicated in the modulation of the hypoglossal nerve. It has been observed that the ablation of this nucleus causes a change in the firing pattern of this cranial nerve.[2]

In addition, the nucleus raphe obscurus mediates expiration via the effect of serotonin and depresses periodic synaptic potentials.[3] It has also been shown that this nucleus stimulates gastrointestinal motor function; microinjections of 5-HT into the nucleus raphe obscurus increase gastric movement.[4]

See also[edit]


  1. ^ Brodal, A. Neurological Anatomy in relation to Clinical Medication 3rd ed. Oxford Press. 1981
  2. ^ Peever JH, Necakov A, Duffin J., "Nucleus raphe obscurus modulates hypoglossal output of neonatal rat in vitro transverse brain stem slices." Journal of Appl Physiol. 2001 Jan;90(1):269-79
  3. ^ Lalley PM, Benacka R, Bischoff AM, Richter DW, "Nucleus raphe obscurus evokes 5-HT-1A receptor-mediated modulation of respiratory neurons". Brain Research Volume 747, Issue 1, 30 January 1997, Pages 156-159
  4. ^ Krowicki, ZK and Hornby, PJ. "Serotonin microinjected into the nucleus raphe obscurus increases intragastric pressure in the rat via a vagally mediated pathway", Pharmacology and Experimental Therapeutics. Volume 265, Issue 1, pp. 468-476, 04/01/1993