Age-related loss of VGLUT1 excitatory, but not VGAT inhibitory, immunoreactive terminals on motor neurons in spinal cords of old sarcopenic male mice

作者：Krishnan, Vidya S.; Shavlakadze, Tea; Grounds, Miranda D.; Hodgetts, Stuart, I; Harvey, Alan R.^*

来源：Biogerontology, 2018, 19(5): 385-399.

DOI：10.1007/s10522-018-9765-5

• VGLUT1
• VGAT
• Astrocytes
• Microglia
• Synaptic transmission
• Proprioception
• Sarcopenia

Age-related changes in ventral lumbar spinal cord (L3-L5) were compared in young [3 month, (M)] and old (27 M) C57BL/6J male mice. The aged mice had previously been shown to exhibit sarcopenia and changes to peripheral nerve morphology. The putative connectivity of beta-III tubulin positive alpha-motor neurons was compared in immunostained transverse sections using excitatory and inhibitory terminal markers vesicular glutamate transporter-1 (VGLUT1) and vesicular GABA transporter (VGAT). Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba1) immunostaining was used to monitor changes in astrocyte and microglial phenotype respectively. For a given motor neuron, the neuronal perimeter was outlined and terminals immunoreactive for VGLUT1 or VGAT in close apposition to the soma were identified. By 27 M, the percentage coverage and total number of VGLUT1 immunoreactive terminals immediately adjacent to the soma of alpha-motor neurons was significantly decreased compared with young mice. However, percentage coverage of immunoreactive VGAT inhibitory terminals did not change significantly with age. The gray matter of 27 M spinal cords showed increased astrocytic and microglial activity. The loss of VGLUT1 terminals on alpha-motor neurons, terminals known to be derived from proprioceptive muscle afferents, may further impair sensorimotor control of hind limb skeletal muscle function in old mice.

• 出版日期2018-10