sentence: These results are in agreement with a study that showed the normalized expression of Nrf2 and HO-1 induced by sulforaphane , another Nrf2 activator , in these brain areas [ 31 ] ; however , in contrast to sulforaphane , oltipraz also potentiated the overexpression of NQO1 in the prefrontal cortex , revealing the different mechanism of action of these compounds in neuropathic pain .