Biology of Addiction Flashcards
What three structures in the brain are involved in the mesolimbic dopamine system (reward pathway)?
Ventral Tegmental Area
Nucleus Accumbens
Projections to medial pre-frontal cortex
Which part of the brain releases dopamine when you use an addictive substance?
Nucleus Accumbens
What is unique about amphetamines as an abusive substance?
Amphetamine use causes 1000x the amount of dopamine release than normal.
Cocaine = 300x Nicotine = 200x
What is the role of MAO?
Degrades neurotransmitters
Order the 5 routes of drug administration from fastest delivery to slowest.
Inhalation
Injection
Snorting/snuffing
Ingestion
What is the mechanism of THC’s action?
Binding to cannabinoid receptors.
What is the mechanism of heroin action?
Binding to opioid receptors.
What is the mechanism of nicotine action?
Binding to A4B2 nicotinic (ACh) receptors in the ventral tegmental area = increased release of DA in the n. accumbens
What is the mechanism of caffeine action?
Prevents adenosine binding
What is the mechanism of both cocaine and amphetamine action?
Blocks dopamine reuptake.
What is the mechanism of action for LSD?
Both an agonist and antagonist.
What has new evidence shown about the activation of certain parts of the brain in addiction?
On top of the reward pathway being activated, other brain systems seem to be activated as well with repeated substance use.
What are some environmental factors that contribute to addiction?
Stress Early abuse Witnessing violence Peers who use drugs Availability of drugs
Recent evidence has shown that __% of risk of addiction is genetic?
50%
It was shown in experiments that the number of DA receptors a person had correlated to how much they liked or disliked a drug. True or False?
True.
People with a high number of dopamine receptors said the drug was unpleasant.
There are 11 criteria for the diagnosis of substance use disorder. What are the number of criteria that need to be met to be categorized as mild, moderate, or severe?
Mild = 2-3 Moderate = 4-5 Severe = > 6
Your patient has been a long time alcohol abuser. What would you see on an MRI image of the brain?
Brain atrophy + Increased ventricle size
What effect does MDMA (ecstasy) have in the CNS?
Selectively destroys your serotonin neurons.
What are the advantages to using partial agonists in treating addiction? (3)
Reduce craving for it and withdrawal
Reduce dependence potential (not a full effect)
Can act as a competitive inhibitor to the actual drug if taken
Buprenorphine is a partial antagonist for treating what type of withdrawal?
Opioid withdrawal.
Hard to overdose because of ceiling effect.
How does varenicline (chantix) work in nicotine addiction treatment?
It is a partial agonist of A4B2 nicotinic receptors and a competitive inhibitor of nicotine itself.
