The origin of centrifugal inner ear fibers of gymnophions (amphibia). A horseradish peroxidase study.
The cells of origin of the centrifugal innervation to the inner ear were investigated in the amphibian order gymnophiona. After applying HRP to the VIIIth nerve inside the otic capsul a Golgi-like labeling was obtained only in a small number of cells in the ipsilateral rhombencephalic basal plate and in the VIIIth nerve afferents. The axons of these cells course after entrance to the raphe and then turn back to the efferent cells in the reticular formation. With respect to the exclusively ipsilateral distribution, the efferent cells of gymnophions resemble those of anurans. With respect to the axon course they resemble those of urodeles, and may thus be regarded as intermediate between the two orders of amphibians. The phylogenetic significance of these findings is discussed.
D000663:Amphibians / Q000033:anatomy & histology*; D000818:Animals; D001001:Anura / Q000033:anatomy & histology; D001933:Brain Stem / Q000033:anatomy & histology*; D007758:Ear, Inner / Q000294:innervation*; D004525:Efferent Pathways / Q000033:anatomy & histology; D005724:Ganglia / Q000033:anatomy & histology; D012154:Reticular Formation / Q000033:anatomy & histology; D013045:Species Specificity; D014562:Caudata / Q000033:anatomy & histology; D000159:Vestibulocochlear Nerve / Q000033:anatomy & histology*