Figure 2. Levels of dopaminergic (DAergic) markers in the rat striatum and substantia nigra pars compacta (SNpc) 3 days after binge methamphetamine (METH).

Rats were treated with four successive injections (i.p.) of either saline (SAL) (1 mL/kg) or METH-HCl (10 mg/kg) at 2-h intervals. Three days later, the animals were sacrificed and brain tissue was harvested. (A) Core body temperature of animals during binge METH or SAL treatment measured 1 h after each injection. METH induced significant hyperthermia over time (***p<0.001 SAL vs. METH, two-way ANOVA with repeated measures followed by Student-Newman-Keuls post hoc test, n=5). (B, C) Quantified dopamine transporter (DAT) and tyrosine hydroxylase (TH) immunoreactivities in the striatum (B) and SNpc (C). METH significantly reduced DAT (−68%) and TH (−33%) levels in the striatum (*p<0.05, **p<0.01, Student’s two-tailed t-test, n=5) and not in the SNpc. (D) Representative western blot images of DAT (72 kDa), TH (64 kDa), and β-actin (45 kDa) from rats administered saline (S) and METH (M). β-Actin immunoreactivity was used as a loading control. All band density values were normalized to the saline controls. (E) Fluorescently labeled DAT (red) and TH (green) in brain tissue slices of the striatum and SNpc. The images depicting the striatum are magnified 40× to show individual axons; the SNpc images are magnified 4× to show the total surface of this area. Channel overlay shows co-localization of green and red signal in yellow. (F) High-contrast images of TH immunoreactivity in striatal brain slices show the morphology of TH-labeled striatal axons. All data are expressed as mean ± S.E.M.