Fig. 2

Expression of tyrosine hydroxylase (TH)-immunopositive (TH+) dopamine (DA) neurons in the substantia nigra pars compacta (SNc) and TH-immunoreactive (TH-ir) dopaminergic nerve fibers in the striatum. The scale bar is 100 µm. a The number of TH+ neurons was decreased in the SNc region of the rotenone (ROT)-injected rats compared to the control (CONT) group. In contrast, nerolidol (NRD) administration rescued the TH+ neurons in the ROT + NRD injected rats compared to the ROT rats. b The expression of TH-ir fibers in the striatum of the CONT, ROT, ROT + NRD, and NRD-only group of rats. c The number of TH+ positive DA neurons in the SNc was counted from each group. A significant decrease (*p < 0.05) in the number of DA neurons was observed in the SNc of the ROT group compared to the CONT group. NRD treatment significantly (^#p < 0.05) protected the DA neurons from the ROT-induced neuronal death. No significant difference was observed in the DA neurons of the CONT and NRD-only group. Values are expressed as percent mean ± SEM (n = 3). d A significant decrease (*p < 0.05) in the TH-ir fibers was observed in the ROT group compared to the CONT group. NRD treatment significantly inhibited (^#p < 0.05) the loss of TH-ir fibers in the ROT + NRD group compared to the ROT group. The CONT rats and NRD-only-injected rats did not show a remarkable loss of TH-ir fibers