Losartan protects DA neurons of the SNpc from MPTP toxicity. (a) TH immunoreactive neurons and Nissl stained cells in the SNpc from mice treated with saline, MPTP, MPTP + losartan or losartan alone. Scale bars equal to 100 μm. Saline panel shows a representative contour selection of the A9 region. The Cell Selection panel shows an example of counted TH+ neurons (indicated with arrows) or Nissl-stained cells with large nuclei (indicated with arrows) and excluded Nissl-stained cells with small nuclei (indicated with arrowheads). (b) Quantification of the number of TH+ neurons and Nissl stained cells in the SNpc, revealed a significant decrease in the number TH+ neurons in MPTP treated mice when compared to saline control treated animals. MPTP-injected mice treated daily with losartan significantly decreased the MPTP-induced loss of TH+ neurons in the SNpc. Significance is indicated by (#) when compared to MPTP-alone injected mice and (*) when compared to saline-alone injected mice (p ≤ 0.05, One-way ANOVA followed by Newman-Keuls post-hoc test). Data are represented as mean ± SEM, n = 4–5 for TH immunostain and n = 3 for Nissl stain.