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35 Cards in this Set

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Antagonist:
drug that blocks the effects of a neurotransmitter
Agonist:
a drug that mimics or increases effects of a neurotransmitter
Mixed agonist-antagonist:
an agonist for some effects (or at some doses) of the transmitter and an antagonist for others
Drugs influence synaptic activity in many ways:
- can increase or decrease the synthesis of the neurotransmitter
- cause it to leak from its vesicles
- increase its release
- or decrease its reuptake
- block its breakdown into inactive chemicals
- act on the postsynaptic receptors
Affinity:
a drug has an affinity for a receptor if it binds to it (like a lock in a key); vary from strong to weak
Efficacy:
a drug's tendency to activate/stimulate the receptor
Drug effectiveness and side effects:
people vary in their abundance for each kind of receptor, so the effectiveness and side effects vary from one person to another
Drugs work by mimicking our own neurochemistry
Drugs alter various stages of synaptic processing
Olds and Milner (1954)
placed rats in a Skinner box that allowed self-stimulation of the brain by the pressing of a lever.
Rats sometimes pressed the lever 2000 times per hour to stimulated the release of dopamine in the nucleus accumbens
Dopamine:
Released during sexual excitement, gambling, video games, and the viewing of “attractive” people.
Dopamine depletion:
rapid brain stimuation depletes the dopamine supply and brain stimulation becomes less reinforcing; mice deficient in dopamine receptors generally do not work to receive cocaine; nearly all abused drugs increase dopamine release; yet not everything we work for causes joy
Berridge and Robinson (1998)
suggest an important distinction be made between “liking” and “wanting” behaviors; Activity and dopamine in the nucleus accumbens seems to be related to “wanting”;
Results in a monopolization of attention (drug abusers want drugs that no longer give them pleasure)
Nucleus accumbens:
small subcortical area rich in dopamine receptors;
an area responsible for feelings of pleasure
Stimulant drugs:
increase excitement, alertness, motor activity and elevate mood.
Examples: amphetamines, cocaine, methylphenidate (Ritalin), MDMA (Ecstasy), nicotine
Amphetamine:
stimulates dopamine synapses by increasing the release of dopamine from the presynaptic terminal by reversing the dopamine transporter
Cocaine:
blocks the reuptake of dopamine, norepinephrine, and serotonin
Methylphenidate:
(Ritalin) also blocks the reuptake of dopamine but in a more gradual and more controlled rate.
MDMA!:
increases the release of dopamine at low doses that account for its stimulant properties.
Increases the release of serotonin at higher doses accounting for its hallucinogenic properties.
Research indicates damage to neurons that contain serotonin.
Degree of risk to humans is not clear.
Nicotine:
the active ingredient in tobacco.
Nicotine stimulates one type of acetylcholine receptor known as the nicotinic receptor.
Nicotinic receptors are found in the central nervous system, the nerve-muscle junction of skeletal muscles and in the nucleus accumbens.
Nicotinic receptors are also abundant in the nucleus accumbens and facilitate dopamine release.
Opiates:
derived from (or similar to those derived from) the opium poppy.
Opiates decrease sensitivity to pain and increase relaxation by attaching to endorphin receptors in the brain.
Examples: morphine, heroin, methadone.
Endorphins:
peptides produced by the brain; Endorphin synapses may contribute to certain kinds of reinforcement by inhibiting the release of GABA indirectly;
Endorphin synapses inhibit ventral tagmental neurons that release GABA;
Inhibiting GABA indirectly releases dopamine
Tetrahydocannabinol (THC):
the active ingredient in marijuana; THC attaches to cannabinoid receptors throughout the brain but especially the cerebral cortex, cerebellum, basal ganglia, and hippocampus; Anandamide and 2-AG are the endogenous chemicals that attach to these receptors; The location of the receptors in the brain may account for the subjective effects of loss of time, an intensification of sensory experience, and also memory impairment; The cannabinoid receptors are located on the presynaptic neuron and inhibit the release of glutamate and GABA
Hallucinogenic drugs:
cause distorted perception;
many hallucinogenic drugs resemble serotonin in their molecular shape; hallucinogenic drugs stimulate serotonin type 2A receptors (5-HT2A) at inappropriate times or for longer duration than usual thus causing their subjective effect
Alcohol:
is a drug that has a long historical use and is used widely throughout the world;
In moderate amounts, alcohol is associated with relaxation.
In greater amounts it impairs judgment and damages the liver and other organs.
Alcoholism/alcohol dependence:
is the continued use of alcohol despite medical or social harm even after one has decided to quit or decrease drinking.
Physiological effects of alcohol:
Inhibition of sodium across the membrane.
Expansion of the surface of membranes.
Decreased serotonin activity.
Enhanced response by the GABAA receptor.
Blockage of glutamate receptors.
Increased dopamine activity.
Two types of alcoholism:
Type I/Type A
Type II/Type B
The genetic basis for early-onset alcoholism is stronger than for later-onset, especially in men
Type I/Type A alcoholism:
Later onset.
Gradual onset.
Fewer genetic relatives with alcoholism.
Equal quantity between men and women.
Less severe.
Type II/Type B alcoholism:
Earlier onset (usually before 25).
More rapid onset.
More genetic relatives with alcoholism.
Men outnumber women.
Often severe.
Often associated with criminality.
Factors contributing to continued substance abuse:
Tolerance develops
Cravings in response to cues
Brain reorganization (nucleus accumbens and prefrontal cortex)
Genes influence the likelihood of alcoholism in various ways:
Sensitivity of Dopamine type 4 receptor
Control of COMT enzyme that breaks down dopamine
Medications to combat alcoholism:
Antabuse.
Methadone.
Many do not respond to other treatments so medications have been used to reduce cravings.
Antabuse (disulfiram):
works by antagonizing the effects of acetaldehyde dehydrogenase; after alcohol consumption, enzymes in the liver metabolize it into a poisonous substance called acetaldehyde; Most studies suggest that Antabuse has been only moderately effective.
When effective, it supplements the alcoholic’s own commitment to quit.
Daily routine of pill ingestion may reaffirm commitment not to drink.
Many quit taking the pill and continue to drink.
Acetaldehyde:
poisonous substance; converted by the enzyme acetaldehyde dehydrogenase into acetic acid, a chemical that the body can use as a source of energy;
accumulation of acetaldehyde results in sickness
Methadone:
an opiate similar to heroin and morphine but is absorbed and metabolized slowly; perceived to be less harmful than other drugs; assumed to satisfy the cravings associated with the previous drug use and allow the person to carry on with their life.