Aging mildly affects Dendritic Arborisation and Synaptic Protein Expression in Human Substantia Nigra Pars Compacta

Publication date: Available online 8 February 2019Source: Journal of Chemical NeuroanatomyAuthor(s): Aditi Naskar, Anita Mahadevan, Mariamma Philip, Phalguni Anand AlladiAbstractThe protein α-synuclein, a major component of Lewy bodies in nigral neurons of aged and Parkinson's disease (PD) patients, normally co-localizes with synaptophysin and regulates the pool of synaptic vesicles. Our earlier study on substantia nigra pars compacta (SNpc) in an Asian-Indian population, demonstrated an age-associated linear but non-logarithmic increase in soluble α-synuclein without any loss of nigral neurons. Another distinctive finding was the presence of activated microglia in the ventrolateral region of the aged nigra, suggesting sub-threshold neurodegeneration. Since microglia prune dendrites, we evaluated the alterations in dendritic arborisation in the SNpc from autopsied midbrains of Asian-Indians through aging, using Golgi-Kopsch protocol. Further, we evaluated the expression of synaptic proteins, synaptophysin and synaptotagmin-11 as parallel markers of synaptic transmission anomalies. The dendritic arborization pattern was typical of large multipolar neurons. A subtle but non-significant decline in parameters like dendritic length and number of intersections was noted. Thus, the alterations were milder than those reported in PD. In the neurons of the young (till 10 years), faint cytoplasmic immunoreactivity of synaptic proteins was noted. In the adults and elderly, it was membr...
Source: Journal of Chemical Neuroanatomy - Category: Neuroscience Source Type: research