Effects of Dopamine Agonists and Drug Use Flashcards
What are dopamine agonists?
Drugs that increase the effectiveness of dopamine.
Name five common dopamine agonist drugs.
Alcohol, weed, amphetamines, Adderall, opioids, caffeine.
What is the effect of dopamine agonists on the prefrontal cortex (PFC)?
Long-term potentiation (LTP) occurs, making the brain associate cues with the drug.
What happens to D2 dopamine receptors after prolonged drug use?
Downregulation — fewer receptors are made, reducing dopamine sensitivity.
What emotional effect can result from dopamine receptor downregulation?
Anhedonia — reduced ability to feel pleasure.
What structural change occurs in VTA neurons with chronic drug use?
They shrink and release less dopamine.
What is the result of decreased dopamine release from the VTA?
Blunted reward response and reduced motivation.
How does chronic drug use affect PFC metabolism?
Decreased metabolic activity — less likely to do the ‘harder right’ thing.
What is the behavioral outcome of reduced PFC function from drug use?
Poor decision-making, impulsivity, and loss of control over behavior.
What is the amygdala’s response to withdrawal?
Increased AP rate, leading to anxiety and discomfort.
What brain circuit is formed that drives compulsive drug-seeking?
LTP between the orbital frontal cortex and dorsal striatum.
What is the function of the orbital frontal cortex in addiction?
Organizes behaviors needed to get the reward of the moment.
What is a physiological sign of addiction in the brain?
Long-term potentiation between orbital frontal cortex and dorsal striatum.
What therapeutic effect does cognitive behavioral therapy (CBT) have on the brain?
Increases PFC metabolism and decreases amygdala activity.
What can reverse the benefits of CBT in recovering addicts?
Stress hormones like norepinephrine and cortisol.
What drug helps prevent relapse by lowering norepinephrine?
Clonidine (a norepinephrine antagonist).
How does gene therapy attempt to reduce alcohol intake?
By inserting more D2 receptor genes into the nucleus accumbens.
What delivery system is used in dopamine gene therapy?
AAV (adeno-associated virus) vectors injected into brain tissue.
What paradoxical result can occur after dopamine gene therapy in monkeys?
They stop drinking but also stop engaging in normal rewarding behavior — loss of flexibility.
