Flashcards in Module 3.3 Deck (35)
Why are our brains so sensitive to plant chemicals?
Because most plants evolve chemicals that either attract or repel insects and those chemicals have an effect on other species too, including humans.
What is an agonist?
An agonist is a drug that enhances the effects of a neurotransmitter.
What is an antagonist?
a drug that decreases the effects of a neurotransmitter
List 6 way in which drugs may effect synaptic function.
1. increase/decrease the synthesis of a neurotransmitter
2. cause its vesicles to leak
3. increase its release
4. decrease its reuptake
5. block its breakdown into inactive chemicals
6. act on the postsynaptic receptors
What is affinity?
A drug has affinity for a receptor if it binds to it
Describe nicotine's effect on dopamine. How are nucleus accumbens cells altered after repeated nicotine exposure?
It increases dopamine at the nucleus accumbens. It causes nucleus accumbens cells to become less responsive.
Describe opiates' indirect effect on dopamine.
Opiates cause the brain to release endorphins that activate dopamine release
What are the psychological and physical effects of marijuana?
Intensified sensory experiences, an illusion that time has slowed down, cognitive and memory impairment
What are the indirect effects of cannabinoids on dopamine?
They increase the activity of neurons that release dopamine.
What neurotransmitter is affected by hallucinogenic drugs?
What type of receptor is made more responsive by alcohol? What other neurotransmitters are affected?
The GABA receptor is made more responsive. Other NTs that are affected are dopamine and opiate receptors.
List the differences between Type I and Type II Alcoholism.
Type I occurs in people older than 25 gradually and they do not have relatives who abuse alcohol. Type II occurs in people younger than 25 with a rapid onset and most have close relatives that are alcoholics.
Describe the evidence of a genetic risk for alcoholism.
People with a longer version of the gene that controls the dopamine type 4 receptor report needing a larger amount of alcohol because they have less sensitive receptors. Another gene is one that makes people more impulsive.
How does the prenatal environment affect risk for alcoholism?
The more alcohol a mother drinks during pregnancy, the more likely the child will develop alcoholism.
Describe the development of tolerance.
After repeated use, pleasure decreases and tolerance develops. This causes people to be less responsive to alcohol and other reinforcement.
Describe the metabolism of alcohol.
The liver metabolizes alcohol to acetaldehyde. The acetaldehyde dehydrogenase converts the acetaldehyde to acetic acid, which the body uses for energy.
What is the biochemical effect of Antabuse? What is its physiological effect when combined with alcohol use?
It antagonizes the effects of acetaldhyde dehydrogenase by binding to its copper ion. It makes you sick.
What are two other medications to treat alcoholism? How do they work?
Revia and Campral. Revia blocks opiate receptors and makes alcohol use less pleasurable. Campral helps with alcohol withdrawal by antagonizing the receptors for glutamate (the brain's main excitatory transmitter)
What is used to treat opiate addiction? Does it end addiction?
Methadone is used to treat opiate addiction. It doesn't end the addiction.
What is efficacy?
a drug's tendency to activate a receptor
How were the brian mechanisms of please and reinforcement discovered?
Two psychologists put an electrode in the septum in a rat's brain and whenever they stimulated that part, the rat responded favorably.
Which brain area is especially important for reinforcement and addiction?
What other activities besides drugs effect the nucleus accumbens?
sex, gambling, video games
What is a common neural mechanism for nearly all abused drugs?
The release of of dopamine and norepinephrine
How do amphetamine and cocaine affect dopamine?
They increase the accumulation of dopamine in the synaptic cleft
What causes the "crash" after amphetamine or cocaine?
The excess dopamine washes away from the synapse faster than the presynaptic cell makes more to replace it
How does Ritalin work? Is it safe for children? Why or why not?
It blocks the reuptake of dopamine. It is safe for children because they are less likely to use drugs later, if they take Ritalin.
How does MDMA (ecstasy) affect neurotransmitters?
In lower doses, it increases dopamine. In larger doses, it increases serotonin.
What evidence points to long-term brain damage after use of ecstasy?
Studies on rodents show that repeated large doses damage neurons that contain serotonin
Addictive drugs increase ________ in the __________.
dopamine; nucleus accumbens
Repeated use of ________ reorganizes the nucleus accumbens so that other stimulation is less rewarding and the drug is more rewarding
Amphetamines and cocaine are
MDMA (ecstasy) in low doses stimulates ______; in high doses stimulates ______
treats addiction to opiates