Localization of motoneurons innervating the extraocular muscles in Salamandra salamandra L. (Amphibia, Urodela).
The central innervation patterns of the extraocular muscles were investigated in the European fire salamander Salamandra salamandra L. by means of the horseradish peroxidase method. The ipsilateral portion of the nucleus nervi oculomotorii, which is located in the rostral ventral tegmentum mesencephali, supplies the musculi recti inferior and medialis and the musculus obliquus inferior without a clear somatotopic representation of the motoneurons. The musculus rectus superior is innervated mainly by a contralateral portion of this nucleus. A definite nucleus Edinger-Westphal could not be recognized. The nucleus nervi trochlearis, which rostrally joins the nucleus nervi oculomotorii with a gap of only about 40 micron between the nuclei, is situated completely contralateral to the musculus obliquus superior supplied by it. The nucleus nervi abducentis, innervating the musculus rectus lateralis, and the nucleus accessorius nervi abducentis, supplying the musculus retractor bulbi, are found in the ipsilateral medulla oblongata and exhibit a large rostrocaudal extension from the eighth cranial nerve to the first root of the vagus nerve. Dendrites of the nucleus nervi oculumotorii and of the nucleus accessorius nervi abducentis extend into neuropil areas receiving primary sensory afferents.
D000010:Abducens Nerve / Q000033:anatomy & histology; D000818:Animals; D008636:Mesencephalon / Q000033:anatomy & histology*; D009801:Oculomotor Muscles / Q000294:innervation*; D009802:Oculomotor Nerve / Q000033:anatomy & histology; D011149:Pons / Q000033:anatomy & histology*; D012454:Salamandra; D014321:Trochlear Nerve / Q000033:anatomy & histology