HIV-1 infection assay. HIV-1SF162 infectivity in human glial was determined based on the relative amount of Tat protein expressed by the virus using a luciferase based assay. (HA) human astrocytes, (R5) HIV-1SF162, (M) morphine at 500 nM, (MVC) maraviroc at 100 nM, (bivalent) compound 49 at 100 nM, and (NTX) naltrexone at 1500 nM. Values are absorbance ± SEM of 3 independent experiments at 18 h post-infection (*p < 0.005 vs. un-infected cells; $p < 0.05 vs. R5 HIV-1; #
p <0.05 vs. opioid; ¶p < 0.05 vs. maraviroc (MVC); §p < 0.05 vs. morphine + MVC; ^
p <0.05 vs. MVC + NTX; ^^
p <0.05 vs. morphine + MVC + NTX; Ω
p <0.05 vs. bivalent) [76].