Journal of neuroscience research
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Canine degenerative myelopathy (DM) is a progressive, adult-onset, multisystem degenerative disease with many features in common with amyotrophic lateral sclerosis (ALS). As with some forms of ALS, DM is associated with mutations in superoxide dismutase 1 (SOD1). Clinical signs include general proprioceptive ataxia and spastic upper motor neuron paresis in pelvic limbs, which progress to flaccid tetraplegia and dysphagia. ⋯ These results indicate that intercostal muscle atrophy in DM is not preceded by physical loss of the motor neurons innervating these muscles, nor of their axons. Axonal loss in thoracic sensory roots and sensory neuron death suggest that sensory involvement may play an important role in DM disease progression. Further analysis of the mechanisms responsible for these morphological findings would aid in the development of therapeutic intervention for DM and some forms of ALS.
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Cochlear ablation triggers cellular and molecular reactions in the adult mammalian central auditory system, leading to complex rearrangements in the cellular networks of the auditory brainstem. The role of microglial cells in these processes is largely unknown. We analyzed morphological and molecular responses as well as cellular affiliations of microglia in the auditory brainstem 1 and 7 days after unilateral sensory deafferentation of the cochlear nucleus. ⋯ By covisualizing cytological markers such as NeuN, GFAP, CD11b, vGluT-1, GAD-65, and Gap43 with the prominent MAP kinases ERK1/2 and p38, we show that MAPK signaling is affected by sensory deafferentation in microglia but not in astroglia or in neurons. In conclusion, microglia displaying MAPK signaling appear to contribute to an adaptive response in central auditory regions that was directly or indirectly affected by sensory deafferentation. Moreover, microglial cells are temporally and spatially in place to participate in synaptogenesis inside VCN.