Drugs, Lec 16 02/26/2014
Two theories on drugs of abuse:
AP gets sent from your midbrain to your forebrain in VTA pathway to nucleus accumbens. Increases
dopamine release in the nucleus accumbens.
1. All compulsions and all drugs of abuse activate this pathway:
Increase dopamine in the nucleus accumbens.
Alcohol, heroin, nicotine, caffeine, Diablo II, internet porn, etc. all activate this pathway.
2. Some drugs do and some don’t (activate the pathway):
If you destroy the dopamine receptors in the nucleus accumbens in rats you lose the reinforcing effect of
the cocaine stimulus on behavioral responses. Stop pressing the lever to get cocaine.
S(R) > R lever press
If you do this after the rats have learned the procedure to press for heroin, they still do it.
If you inject narcan into the nucleus accumbus, specifically in the central gray, shifts the IVSA of analgesic
effects of heroin to the right.
Analgesia is mediated by the central gray in your midbrain.
Loaded with endorphins, helps your body manage pain. Nucleus accumbens is responsible for
the reinforcing effects of opioids and all drugs of abuse.
Dopamine is for learnin