BDNF and heroin dependence: In rat, cocaine causes learning and memory impairments involve the mechanism of oxidative stress, which could participate in drug addiction and drug toxicity.[14,15] Recent researches have investigated that BDNF and oxidative stress markers thiobarbituric acid reactive substances took participation in heroin addiction include cerebral plasticity and impairment, which could reflect the severity of drug abuse.[16] Therefore, it was not only that BDNF but also oxidative stress markers played the role in addiction.