Fig. 1.

HIV Tat enhanced MA-induced upregulation of cytokines. (a) Administration of MA (3×10 mg/kg) or Tat (10 µg) alone significantly increased the IL-1β in the substantia nigra, whereas a combination of both treatments induced further upregulation and sustained expression of IL-1β (N=7–9 rats per group); (b) administration of either MA or Tat significantly increased the TNF-α in the substantia nigra, whereas a combination of both treatments further increased the expression of TNF-α (N=7–9 rats per group). *P<0.05; **P<0.01. MA, methamphetamine; Tat, transactivator of transcription.