Interestingly,dopamine has been reported to be a potent inducer of HO-1.20,21,35 In 1999, Schmidt and co-workersreported that DA dose-dependently induces HO-1 mRNA in C6 glioma cellsand astrocytes.20 It was found that micromolar(1–100 μM) and even submicromolar (100 nM) concentrationsof DA upregulated the expression of HO-1. This evidence concerns the gene HMOX1 and glioma.