Nucleus raphe obscurus

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| Name = Nucleus raphe obscurus

| Latin = nucleus raphes obscurus

| Image = Gray694.png

| Caption = Section of the medulla oblongata at about the middle of the olive. (Raphe nuclei not labeled, but 'raphe' labeled at left.)

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The nucleus raphe obscurus is one of the medullary raphe nuclei. It is located caudal to the nucleus raphe magnus. The nucleus raphe obscurus projects to the cerebellar lobes VI and VII and to crus II along with the nucleus raphe pontis.{{cite book|last1=Brodal|first1=A|title=Neurological Anatomy in relation to Clinical Medication|edition=3rd|publisher=Oxford Press|date=1981|isbn=978-0195026948|url-access=registration|url=https://archive.org/details/neurologicalanat0003brod}}

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.{{cite journal |last1=Peever |first1=JH |last2=Necakov |first2=A |last3=Duffin |first3=J |title=Nucleus raphé obscurus modulates hypoglossal output of neonatal rat in vitro transverse brain stem slices |journal=Journal of Applied Physiology |date=2001 |volume=90 |issue=1 |pages=269–279 |doi=10.1152/jappl.2001.90.1.269|pmid=11133919 }}

In addition, the nucleus raphe obscurus mediates expiration via the effect of serotonin and depresses periodic synaptic potentials.{{cite journal |last1=Lalley |first1=PM |last2=Benacka |first2=R |last3=Bischoff |first3=AM |last4=Richter |first4=DW |title=Nucleus raphe obscurus evokes 5-HT-1A receptor-mediated modulation of respiratory neurons |journal=Brain Research |date=1997 |volume=747 |issue=1 |pages=156–159 |doi=10.1016/S0006-8993(96)01233-4|pmid=9042541 }} It has also been shown that this nucleus stimulates gastrointestinal motor function; microinjections of 5-HT into the nucleus raphe obscurus increase gastric movement.{{cite journal|last1=Krowicki|first1= ZK |last2= Hornby|first2= PJ|title=Serotonin microinjected into the nucleus raphe obscurus increases intragastric pressure in the rat via a vagally mediated pathway|journal=Journal of Pharmacology and Experimental Therapeutics|volume= 265| issue =1|pages= 468–476|date=1993|pmid=8097247}}