Figure 4

METH triggers an early increase in TNF-α protein levels. The effect of 1 mM METH on the (A, C) extracellular and (B, D) intracellular TNF-α levels was evaluated after (A, B) 1 h and (C, D) 24 h of drug exposure by ELISA. As a positive control we used 1 μg/mL LPS. Data are expressed as mean ± SEM of pg/mL for release and pg/mg of total protein for the intracellular levels (n = 3 to 13). ^** P <0.01, ^*** P <0.001, Dunnett’s post-test, significantly different from control. ELISA: enzyme-linked immunosorbent assay; LPS: lipopolysaccharide; METH: methamphetamine; SEM: standard error of the mean; TNF-α: tumor necrosis factor-alpha.