Populations of myelinated nerve fibers in the C8 and L4 ventral and dorsal roots in the opossum, Monodelphis domestica.
A quantitative light-microscopic analysis of the ventral and dorsal roots at the C8 and L4 segments of the spinal cord was made in the opossum, Monodelphis domestica, to evaluate the number of myelinated fibers and their class distribution, and will serve as a baseline to a study of myelinogenesis in that species. In male opossums, the C8 ventral root comprises an average of 595 myelinated fibers (70.3% alpha: 29.7% gamma) and the dorsal root 1,124 fibers (29.4% type I: 41.2% type II: 29.4% type III). The L4 ventral root has an average of 831 fibers (57.9% alpha: 42.1% gamma), and the dorsal root 2,079 fibers (17.4% type I:44.7 type II: 37.9% type III). The females have less fibers but their size and class proportions are comparable to those of the males. These data are discussed in relation to peripheral innervation and are compared to those reported for the rat and the cat.
Leblond
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Département de Sciences Biologiques, Université de Montréal, Qué., Canada.
Cabana
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D000704:Analysis of Variance; D000818:Animals; D005260:Female; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D009893:Opossums / Q000033:anatomy & histology*; D013126:Spinal Nerve Roots / Q000166:cytology*