Effects Of Bilateral Lesions Of Habenula On Motivation Of Heroin Induced Drug Seeking

In China, heroin is abused and harmful. The focus of the current research on drug addiction is the mesolimbic dopamine system, which is the main brain substrate of the reward system. However, the downward forebrain-midbrain negative feedback control system of the reward system has attracted less interest.Habenular (Hb), the relay station of the feedback control system, and is conservative in evolution, possesses important anatomical location with multiple biological functions including endocrine, reward, breathing, emotion, motive, pain, maternal behaviors, reproductive behavior, sleep and et al. It is also helpful for abhor control behavior, attention, learning, memory and et al. All of these functions is related to heroin addiction. But until recent years, the relationship between Hb and drug addiction was causing concern. They found Hb is a major reward center, a dopamine-mediated negative reward effects and the most obvious parts of drug abuse damage in the morphology. However, our previous results show that Hb didn't affect heroin self-administration.In order to clarify the role of the Hb in heroin addiction, we used techniques such as bilateral electrolytic lesion, intravenous self-administration, microdialysis and the task of reward-related learning. At last, we found that bilateral lesions of the Hb caused marked increase of basal release of dopamine the shell of the nucleus of acumbens, however, the acute reinforcing effect of heroin was not changed. Also, we found that Hb lesion caused increased heroin motivation as manifested by increased heroin-associated Pavlovian conditioning and further intensified instrumental conditioning. The results suggested that Hb might play an important role in the drug seeking motive.