Figure 5

Synergistic neurotoxicity of HIV proteins, cocaine and methamphetamine. Human fetal neuronal cultures were treated with HIV proteins, gp120 and Tat alone or in combination with varying concentrations of either methamphetamine or cocaine. Cell death and mitochondrial membrane potentials were monitored, at 16 hours and 6 hours respectively, in these cultures as described in methods. Subtoxic concentrations of gp120 and Tat synergize with methamphetamine (A) and cocaine (B) in a dose responsive manner to cause neuronal cell death. (C) Tat (80 nM) when combined with subtoxic concentrations of gp120, methamphetamine or cocaine causes significant decreases in mitochondrial membrane potential. Synergism is also noted when the combined subtoxic concentrations of gp120 (30 pM) + Tat (40 nM) are co-incubated with either methamphetamine or cocaine. ^*P < 0.05, ^**P < 0.005