STAMBP and melanoma: Furthermore, bicuculline significantly upregulated cAMP levels from 42.6 ± 5.6 to 282.6 ± 5.6 pg/mL in B16F10 melanoma cells and potently reversed the GABA-induced decrease in cAMP levels (from 144.74 ± 7.3 to 333.64 ± 11.47 pg/mL) in α-MSH-treated B16F10 cells (Figure 5D).