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The Neurobiology of Drug Addiction

5: Rats self-administer heroin

Rats self-administer heroin

Just as a rat will stimulate itself with a small electrical jolt (into the reward pathway), it will also press a bar to receive heroin. In this image, the rat is self-administering heroin through a small needle placed directly into the nuclues accumbens. The rat keeps pressing the bar to get more heroin because the drug makes the rat feel good. The heroin is positively reinforcing and serves as a reward. If the injection needle is placed in an area nearby the nucleus accumbens, the rat won't self-administer the heroin. Scientists have found that dopamine release is increased within the reward pathway of rats self-administering heroin. Increased dopamine in this circuit reinforces the behavior of taking the drug—essentially "teaching" the brain to repeat the action. 

This page was last updated November 2019

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NIDA. (2019, November 19). The Neurobiology of Drug Addiction. Retrieved from https://www.drugabuse.gov/neurobiology-drug-addiction

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