Association of dopamine DA-D 2 receptor in rotenone-induced cytotoxicity in PC12 cells

The investigations were aimed to study the possible association of dopamine DA-D₂ receptor in rotenone-induced cytotoxicity in PC12 cells, one among the most studied cell line in neurotoxicity studies. PC12 cells were subjected to receive an exposure of rotenone (10^-6 to 10^-4 M) for 24 and 48 hours. Cytotoxicity studies were carried out using standard end points including, (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT), lactate dehydrogenase (LDH) release and neutral red uptake (NRU). Cells were found to be vulnerable to rotenone in dose-dependent manner. In general, 10^-4 and 10^-5 M concentrations were found to be cytotoxic, whereas 10^-6 M and lower concentrations used have shown nonsignificant effect on cell viability. Further, studies were extended to study the rotenone-induced alterations in cellular glutathione (GSH) level and dopamine DA-D₂ receptor expression. Significant (p < 0.001) chronological depletion in GSH levels were recorded following rotenone exposure. Expression of dopamine DA-D₂ receptor was also found to be effected significantly (p < 0.001) at 24 hours of rotenone exposure (10^-4 and 10^-5). However, no further depletion in the expression of dopamine DA-D₂ receptor could be recorded with extended exposure period, that is, 48 hours. Rotenone at 10^-6 M and lower concentrations was found to be ineffective in PC12 cells. Data suggest the vulnerability of PC12 cells against experimental exposure of rotenone, which possibly routed through dopamine DA-D₂ receptor and oxidative stress machinery.