Impact of Aging on Proprioceptive Sensory Neurons and Intrafusal Muscle Fibers in Mice
| Autor: | Sydney K. Vaughan, Gregorio Valdez, Olivia L. Stanley |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Male
0301 basic medicine Aging Sensory Receptor Cells Muscle Fibers Skeletal Muscle spindle Neuromuscular Junction Sensory system Neurotrophin-3 Tropomyosin receptor kinase C Mice 03 medical and health sciences 0302 clinical medicine Atrophy Neurotrophin 3 Ganglia Spinal Animals Medicine Receptor trkC Neurons Afferent Proprioception biology business.industry medicine.disease Axons Middle age Tissue Degeneration 030104 developmental biology medicine.anatomical_structure biology.protein Original Article Geriatrics and Gerontology business Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. :glw175 |
| ISSN: | 1758-535X 1079-5006 |
| DOI: | 10.1093/gerona/glw175 |
| Popis: | The impact of aging on proprioceptive sensory neurons and intrafusal muscle fibers (IMFs) remains largely unexplored despite the central function these cells play in modulating voluntary movements. Here, we show that proprioceptive sensory neurons undergo deleterious morphological changes in middle age (11- to 13-month-old) and old (15- to 21-month-old) mice. In the extensor digitorum longus and soleus muscles of middle age and old mice, there is a significant increase in the number of Ia afferents with large swellings that fail to properly wrap around IMFs compared with young adult (2- to 4-month-old) mice. Fewer II afferents were also found in the same muscles of middle age and old mice. Although these age-related changes in peripheral nerve endings were accompanied by degeneration of proprioceptive sensory neuron cell bodies in dorsal root ganglia (DRG), the morphology and number of IMFs remained unchanged. Our analysis also revealed normal levels of neurotrophin 3 (NT3) but dysregulated expression of the tyrosine kinase receptor C (TrkC) in aged muscles and DRGs, respectively. These results show that proprioceptive sensory neurons degenerate prior to atrophy of IMFs during aging, and in the presence of the NT3/TrkC signaling axis. |
| Databáze: | OpenAIRE |
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