Absence of age-related changes in nigral dopaminergic neurons of Asian Indians: Relevance to lower incidence of Parkinson's disease

Increased Oxidative Damage and Decreased Antioxidant Function in Aging Human Substantia Nigra Compared to Striatum: Implications for Parkinson’s Disease

“…The same procedure of autopsy, tissue handling and other procedures were uniformly maintained for all the samples in this study. Similar tissues from the human brain bank have been earlier utilized extensively as control samples in PD research [24][25][26][27] and other studies [28][29][30][31][32].…”

Expression of GDNF receptors GFRα1 and RET is preserved in substantia nigra pars compacta of aging Asian Indians

“…When bright field microscopic images are used for densitometric quantification of immunoreactivity in melanized neurons, presence of unbleached neuromelanin influences the grey values (Kastner et al, 1992), therefore we adopted similar staining protocol for the present study also. Following bleaching, the antigen binding epitopes were unmasked by heating the sections in a microwave, in 0.01 M citrate buffer (pH 6.01) at high temperature (level 4) for 10 min (Alladi et al, 2009). Endogenous peroxidase was quenched by incubating the sections in 70% methanol containing 0.03% H 2 O 2 for 30 min at room temperature, in dark.…”

“…For each step, 0.01 M phosphate buffered saline (PBS) containing 0.02% Triton X-100 (PBS-Tx) was used for washing as well as a dilutant for antibody solutions. For negative controls of GFRa1 immunostaining the sections were processed identically, however, the primary antibody was replaced with the dilution buffer, as per our earlier protocol (Alladi et al, 2009). Additionally we used blocking peptide [RET(C-19)-P, Santa Cruz Biotechnology Inc, CA, USA] to pre-adsorb the primary antibody for negative controls for RET immunohistochemistry.…”

“…This was followed by incubation with goat anti-RET primary antibody (1:1000; sc-167-G; Santa Cruz Biotechnology Inc, CA, USA; Table 2) for 72 h. Antigoat secondary antibody tagged to CY3 was used to detect RET binding (1:500; Sigma-Aldrich, CA, USA). Finally, before labeling the sections with TH, the sections were once again washed with 0.01 M PBS-Tx, blocked with 5% BSA and incubated with mouse anti-TH antibody (1:1000; sc-25269, Santa Cruz Biotechnology Inc, CA, USA) (Alladi et al, 2009). An anti-mouse CY5 (1:500; Sigma-Aldrich, CA, USA) was used to detect TH labeling.…”

“…Moreover, in view of preservation of dopaminergic neurons in the Asian Indians (Alladi et al, 2009), the effect of aging on GDNF receptors in this population would yield valuable information. In the present study, we therefore investigated the expression of GFRa1 and RET receptors in SNpc by immunohistochemistry, and using stereology we quantified the numbers of dopaminergic neurons expressing these receptors and assessed the staining intensity using densitometry based image analysis to examine their levels of expression.…”