Origin of bainstem projections to spinal cord

Objective To research the origins of the afferent neurofibers of the 6th lumbral and 1st sacral spinal cord segments in rats.Methods Horseradish peroxidase (HRP) was injected into the spinal cord of rats. After 72 hours, rats were killed and the brainstem were removed. The 40μm serial coronal sections were sectioned and stained with TMB method. These sections were redyed with neutral red and the one side of the 6th lumbral and 1st sacral spinal cord observed under microscope.Results HRP labeled cells were found in the following nuclei: (1) Midbrain: central gray, Edinger-Westphal nucleu, posterior commissure nucleuss, Cajal interstitial nucleus, locus coeruleus, subcoeruleus, pedunculopontine tegmental nucleus, cuneate nucleus, lateral lemniscus nucleus. The distributions of labeled cells in the last two nuclei were contralateral prominance, other ipsilateral prominance. (2) Pons and medulla: medial vestibular nucleus, lateral vestibular nucleus, caudal vestibular nucleus, pontine caudal reticular mucleus, pontine oral reticular nuclleus, gigantocellula reticular nucleus, lateral paragigantocellular nucleus, dousal paragigantocellular nucleus, parvocellular reticularnucleus, dorsal paramedian nucleus, paramedian reticular nucleus, lateral reticular nucleins, ventual reticular subnucleus of medulla lblongata central reticular nucleus, raphe magnus nucleus, raphe pallidus nucleus and raphe obscurus nucleus. The distribrtions of labeled neurons were ipsilateral prominance.Conclusion The afferents of the 6th lumbral and 1st sacral spinal cord extensively origin from the brainstem of rats. It implies that function of lumbrosacral spinal cord is multiplex.