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Supramedullary afferents of the nucleus raphe magnus in the rat: A study using the transcannula HRP gel and autoradiographic techniques
Author(s) -
Carlton Susan M.,
Leichnetz George R.,
Young Eric G.,
Mayer David J.
Publication year - 1983
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.902140105
Subject(s) - nucleus raphe magnus , serotonergic cell groups , zona incerta , nucleus , dorsal raphe nucleus , anatomy , periaqueductal gray , spinal trigeminal nucleus , hypoglossal nucleus , raphe nuclei , spinal cord , medulla oblongata , dorsal column nuclei , cuneate nucleus , neuroscience , vestibular nuclei , chemistry , biology , central nervous system , midbrain , nociception , serotonin , serotonergic , biochemistry , receptor
Afferents of the nucleus raphe magnus (NRM) were retrogradely la‐belled by using a transcannula HRP gel technique in conjunction with tetramethylbenzidine nuerohistochemistry to determine the sources of in‐puts to the nucleus which could potentially influence the descending antio‐ciceptive raphe‐spinal system. Large numbers of HRP‐labelled neurons were seen in the frontal cortex, dorsomedial nucleus of the hypothalamus, zona incerta, nucleus parafascicularis prerubralis (NPfPr), pretectum, dorsal and lateral periaqueductal gray, nucleus cuneiformis (NC), deep superior col‐liculus (dSC), a paraoculomotor cell group which may be the medial acces‐sory nucleus of Bechterew, dorsal column nuclei, and spinal trigeminal nucleus. Smaller numbers of labelled cells were also observed in the preoptic area, nucleus of Darkschewitsch, ventral peri(third)ventricular gray, nu‐cleus reticularis pontis oralis and caudalis, medial and lateral vestibular nuclei, and a subdivision of the hypoglossal nucleus. Confirmational an‐terograde autoradiographic studies were performed by injecting tritiated leucine into two of the principal sources of afferents to NRM: NPfPr, and dSC/NC. The results are compared with control HRP gel implants in the inferior olive, spinal cord, nucleus reticularis paragigantocellularis, and medial fa‐cial nucleus. Comments are also made concerning the parcellation of the ventromedial medulla and the possible role of both NRM and its afferents in central analgesic mechanisms.