Chapter 6: How Drugs and Hormones Influence Behaviour Flashcards
substances that act to alter mood, thought or behaviour; is used to manage neuropsychological illness, may be taken recreationally
psychoactive drugs
the way a drug enters and passes through the body to reach its target
route of administration
5 ways drugs can be administered
- orally
- inhaled into the lungs
- rectally in a suppository
- absorbed from patches applied to the skin or mucous membranes
- injected into the bloodstream, muscle, or brain
injecting a drug directly into the brain allows it to ___ because ___
act quickly in low doses; it encounters few barriers
taking drugs ___ is the safest, easiest and most convenient way to administer them
orally
drugs that are weak acids pass from the ___ into the ___
stomach; bloodstream
drugs that are weak bases pass from the ___ to the ___
intestines; bloodstream
drugs injected into ___ encounter more barriers than do drugs inhaled
muscle
drugs ___ encounter few barriers en route to the brain
inhaled into the lungs
drugs ___ encounter the fewest barriers to the brain but must be hydrophilic
injected into the bloodstream
drugs ___ are absorbed thru the skin and into the bloodstream
contained in adhesive patches
drugs in __ form are absorbed more readily, while drugs in ___ form are not absorbed unless the stomach’s gastric juices can dissolve them
liquid; solid
the drug is diluted by the approx. ___ of blood that circulate an adult body, and when it leaves the bloodstream, the body’s roughly ___ of extracellular fluid further dilute it
6 litres; 35 litres
with each obstacle eliminated en route to the brain, a drug’s dosage can be reduced by a factor of __
10
drugs that are prepared for ___ are much cheaper per dose because ___
inhalation or intravenous injection; the amount required is so much smaller than that needed for an effective oral dose
the body’s barriers to internal movement of drugs
- cell membranes
- capillary walls
- placenta
why is the passage of drugs across capillaries in the brain difficult?
the blood-brain barrier blocks passage of most water-soluble substances
___ can compromise the integrity of the blood-brain barrier, letting ___ through
injury or disease; pathogens
none of the brain’s neurons are farther than ___ from a capillary
50 micrometers
brain capillaries are composed of a single layer of ___
endothelial cells
how are endothelial cells in the body different from those in the brain?
- in the body endothelial cells in capillary walls are not fused, so substances can pass through the clefts between the cells
- in the brain, endothelial cell walls are fused to form tight junctions, so molecules of most substances cannot squeeze between them
endothelial cells of brain capillaries are surrounded by ___
the end feet of astrocytes attached to/covering most of the capillary wall
___ provide a route from the exchange of food/waste between capillaries + the brain’s extracellular fluid
astrocytes
3 barrier-free brain sites
- pineal gland
- pituitary gland
- area postrema
entry of chemicals that affect day-night cycles
pineal gland
entry of chemicals that influence pituitary hormones
pituitary gland
entry of toxic substances that induce vomiting
area postrema
molecules of vital substances cross the blood-brain barrier in 2 ways
- small molecules like O2, CO2 & lipid-soluble molecules can pass through endothelial membranes
- complex molecules of glucose, amino acids & other foods are carried across the membrane by active transport systems or ion pumps
after a drug is administered, the body begins to break it down through ___, which takes place in ___, then excretes the drug
catabolism; kidneys, liver, intestines
the ___ has a family of enzymes involved in drug catabolism called the ___
liver; cytochrome P450 enzyme family
substances that cannot be catabolized/excreted can build up in the body and become ___
toxic
the metal ___ is not easily eliminated and can produce ___
mercury; severe neurological effects
why are metabolized drugs discharged into the environment an issue?
- substances often reingested by many other animals
- may affect fertility, development in high-risk groups such as embryos/juveniles, and physiology/behaviour of adult organisms
the 5 major steps in neurotransmission at a synapse - each a potential site of drug action
- synthesis
- packaging/storing
- release
- receptor interaction
- inactivation by reuptake or degradation
substance that enhances neurotransmitter function
agonists
substance that blocks neurotransmitter function
antagonists
ACh ___ excite muscles, increasing muscle tone, whereas ACh ___ inhibit muscles, decreasing muscle tone
agonists; antagonists
Black widow spider venom acts as an ___ by promoting ___ release to excess
agonist; ACh
botulinum toxin acts as an ___ by blocking ___ release
antagonist; ACh
medical uses of botulin
- can selectively paralyze muscle, blocking excessive muscular twitches or contractions, including spasms that make movement difficult in cerebral palsy
- cosmetically used to paralyze facial muscles that cause wrinkling
Curare acts as an ACh ___
antagonist
nicotine acts as an ACh ___ by ___
agonist; fitting into its receptors’ binding sites and opens the ion channel
hunters in South America did not poison themselves from the curare in their catch because ___
ingested curare cannot pass from the gut into the body
___ muscles are more sensitive to curare-like drugs than are respiratory muscles
skeletal
___ inhibit acetylcholinesterase (AChE), the enzyme that breaks down ACh, thus increasing the amount available in the synapse
physostigmine & organophosphate agonists
___, obtained from an African bean, is also used as a poison by hunters
physostigmine
large doses of physostigmine can be toxic because ___
they produce excessive excitation of the neuromuscular synapse, disrupting movement and breathing
in small doses, ___ is used to treat myasthenia gravis
physostigmine
many insecticides and chemical weapons are ___
organophosphates
insects use glutamate as a neurotransmitter at the nerve-muscle junction, but elsewhere in their nervous system they have ___
nicotinic receptors
___ poison insects by acting centrally, but poison chordates by acting peripherally as well
organophosphates
the government of Syria used ___ in 2013 and 2017 on its own citizens
the lethal nerve gas Sarin, a potent organophosphate agent
___ can readily pass the blood-brain barrier, while ___ cannot
physostigmine & nicotine; curare
physostigmine-like drugs have beneficial effects for ___
memory disorders
decrease in response to a drug with the passage of time
tolerance
who conducted an experiment on tolerance in a prison
Harris Isbell
conclusion of Isbell’s tolerance experiment
much more alcohol was required to obtain the same level of intoxication that was produced at the beginning due to tolerance
3 kinds of tolerance
- metabolic
- cellular
- learned
the # of enzymes needed to break down alcohol in the liver, blood and brain increases, resulting in alcohol consumed being metabolized more quickly + blood alcohol levels falling
metabolic tolerance
brain cell activities adjust to minimize the effects of alcohol in the blood; can help explain why behavioural signs of intoxication may be so low despite a relatively high blood alcohol level
cellular tolerance
explains a drop in outward signs of intoxication; as people learn to cope w/ the demands of living under the influence of alcohol, they may no longer appear intoxicated
learned tolerance
who experimented on rats to observe learned alcohol tolerance?
John Wenger
what was the conclusion of Wenger’s experiment on alcohol and rats?
with motor experience, animals can learn to compensate for being intoxicated
___ develops with repeated drug use, while ___ is more likely to develop with intermittent use
tolerance; sensitization
who used rats to observe drug sensitization?
Terry Robinson and Jill Becker
the neural basis of sensitization lies in part in changes at the ___
synapse
studies on the dopamine synapse after sensitization to amphetamine show more dopamine in the ___ in sensitized animals
synaptic cleft
sensitization can be associated with changes in:
- # of receptors
- rate of transmitter metabolism
- transmitter reuptake
- # /size of synapses
who administered flupentixol to rats to influence their performance in swim tests?
Ian Whishaw
who gave amphetamine to rats with a home group showing no sensitization and an out-group showing robust sensitization?
Sabina Fraioli
sensitization is relevant in 3 ways to understanding psychopharmacological effects of drugs
- many drug therapies must be taken for several weeks before they produce beneficial effects
- sensitization is related to drug dependence
- life experience, especially stressful ones, can produce effects resembling sensitization that prime the nervous system for addiction
behaviour in which non-human animals self-medicate
zoopharmacognosy
offers a classification system for diagnosing neurological/behavioural disorders
DSM (diagnostic and statistical manual of mental disorders)
caffeine drinks are consumed daily by about __% of adults in the US
85
a cup of coffee contains about ___ of caffeine & some energy drinks as much as ___ of caffeine
100mg; 500mg
caffeine has a very similar structure to ___ and binds to its receptors without activating them, thereby blocking the effect of it and acting as an ___
adenosine; adenosine antagonist
endogenous adenosine induces ___ and caffeine works in opposition, making us feel ___
drowsiness; more alert/peppy
___ inhibits an enzyme that breaks down the second messenger, cyclic adenosine monophosphate (cAMP), leading to increased ___ production, making more ___ available and allowing higher rates of ___
caffeine; glucose; energy; cellular activity
caffeine promotes the release of other neurotransmitters such as ___, which stimulates effects that improve ___
dopamine & acetylcholine; reaction time, wakefulness, concentration and motor coordination
withdrawal symptoms are avoided by continuing to consume caffeine daily but will fade in about ___ days if given up altogether
4-7
caffeine is found in ___
the seeds/nuts/leaves/nectar of plants native to East Asia + South America
___ acts as a natural pesticide, discouraging/killing herbivorous ___ & inhibiting the invasion/colonization of ___
caffeine; insects; pathogenic fungi
nicotine is found in the leaves of the tobacco plant ___
nicotiana tabacum
___ is found in small amounts in potatoes, tomatoes and eggplant
nicotine
at low doses, nicotine is a ___, but at very high doses, it dampens ___
stimulant; neuronal activity
tobacco smokers report feelings of ___
relaxation, sharpness, calmness, alertness
when smoke from a tobacco cigarette is inhaled, within a few seconds nicotine stimulates ___ receptors, which then indirectly causes the release of ___
acetylcholine nicotinic; acetylcholine, norepinephrine, epinephrine, arginine vasopressin, serotonin, endorphins, dopamine
smoking cessation leads to ___
heightened anxiety, irritability, craving, inability to feel pleasure, and tremors
the total amt of nicotine in one cigarette, if injected, can be ___
lethal
respiratory diseases, lung cancer, and related negative effects are caused by ___ rather than in nicotine itself
the harmful chemicals found in tobacco smoke
the long-term health effects of e-cigarettes are likely ___ serious than those of tobacco smoke but are unknown
less
while smoking is a risk factor for ___, cholinergic ___ are medically prescribed to treat it
Alzheimer’s; agonists
acetylcholinesterase inhibitors, such as ___, raise ACh levels and may provide a small benefit to Alzheimer disease
tacrine (Cognex)
at low doses, GABAergic agonists ___; at medium doses, they ___; at high doses, they ___; at very high doses, they ___
reduce anxiety; sedate; anesthetize/induce coma; can kill
the GABAa receptor contains a site where ___ binds, another separate site where ___ binds, another site where ___ bind, and a ___ channel
GABA; alcohol; benzodiazepines; chloride ion
sedative-hypnotic drugs (alcohol) increase ___ binding, thereby ___
GABA; maximizing the time the pore is open
antianxiety drugs (benzodiazepines) influence ___
the frequency of pore opening
because their different actions summate, ___ and ___ should not be taken together
sedative-hypnotic drugs (alcohol) + antianxiety drugs (benzodiazepines)
due to the influx of Cl- and hyperpolarization of the cell membrane, GABA produces its inhibitory effect by ___
decreasing a neuron’s firing rate
benzodiazepines are a class of chemicals that include ___ and are medically prescribed to
- diazepam (valium)
- alprozolam (xanax)
- clonazepam (Klonopin)
reduce anxiety
a characteristic feature of benzodiazepine drugs is that a user who takes repeated doses develops a ___ for them
tolerance
___ results from when the tolerance for one drug, like benzodiazepines, is carried over to a different member of the drug group
cross-tolerance
the fermentation of sugar into alcohol dates back to ___
at least 9000 years
alcohol consumption has short-term psychological/physiological effects that depend on factors like ___
- amt & concentration of alochol
- duration over which it is consumed
- amt of food eaten
- consumer’s weight
- consumer’s experience w/ alcohol
small amts of alcohol typically cause an overall
- improvement in mood
- possible euphoria
- increased self-confidence & sociability
- decreased anxiety
- impaired judgement & fine muscle coordination
- flushing of the face
medium doses of alcohol result in
- lethargy
- sedation
- balance problems
- blurred vision
high doses of alcohol lead to
- profound confusion
- slurred speech
- staggering
- dizziness
- vomiting
very high doses of alcohol cause
- stupor
- memory loss
- unconsciousness
- life-threatening respiratory depression
- inhalation of vomit
long-term and frequent consumption of alcohol can lead to ___
- increased risk of alcoholism
- enormous economic burden
alcoholism costs ___ in the US alone
$249 billion
alcoholics are often ___ and typically have ___
malnourished; elevated levels of chronic pancreatitis, liver disease, cancer
alcoholism results in
damage to the central & peripheral nervous systems, as well as nearly every other system and organ in the body
drugs that act on GABA receptors also affect ___
brain development
range of physical and intellectual impairments observed in some children born to alcoholic parents
fetal alcohol spectrum disorder (FASD)
children with FASD have
- wide spacing between their eyes
- small size with abnormal gyri
- abnormal clusters of cells
- misaligned cells in cortex
FASD behavioural symptoms in children
- learning disabilities
- low intelligence test scores
- hyperactivity/other social problems
- 19x more likely to be incarcerated
prevalence of FASD in the US
around 1-10%
women who are most at risk for bearing FASD babies
- poor/uneducated
- alcohol problems predate pregnancy
- little access to prenatal care
severity of effects of FASD is related to
when/how much/how frequently alcohol is consumed over the course of pregnancy
effects of FASD are worse if
alcohol is consumed in the first trimester, a time of organogenesis and highest levels of DNA synthesis
severe FASD is more likely to coincide with
- binge drinking
- poor nutritional health of mother
- mother’s use of drugs including nicotine
alcohol use by mothers/fathers before conception can change
the methylation status of some genes that contribute to disabilities found on the spectrum
___ of alcohol per day during pregnancy can lead to a decrease in children’s intelligence test scores
1 drink
discriminating features of FASD (diagram)
- short palpebral fissures
- short nose
- flat midface
- indistinct philtrum
- thin upper lip
associated features of FASD (diagram)
- low nasal bridge
- minor ear anomalies
- epicanthal folds
- small jaw
the convolutions characteristic of the brain of a healthy child at age 6 weeks are ___ in the brain of a child with FASD
grossly underdeveloped
the glutamatergic system has several receptors, such as
NMDA, AMPA and kainate
antagonists for the NMDA receptor, such as ___, can produce hallucinations and out-of-body experiences
phencyclidine (PCP/angel dust) and ketamine (special K)
research indicates that PCP inhibits ___ as well as ___, making it a ___
nicotinic acetylcholine receptors; dopamine reuptake; dopaminergic agonist
both PCP and ketamine are known as ___, which are ___ because they distort ___
dissociative anesthetics; compounds that produce feelings of detachment/dissociation from the environment & self; perceptions of sight/sound
___ is medically prescribed for starting/maintaining anesthesia, as it induces a ___
ketamine; trance-like state while providing pain relief, sedation, and memory loss
ketamine is being tested for use in treating
major depressive disorder
ketamine’s mechanism of action, as a ___, is different from most modern drugs prescribed to reduce depression, which operate on ___
glutamatergic agonist; serotonin & norepinephrine targets
___ is an NMDA antagonist that is prescribed in the treatment of Alzheimer disease to prevent ___
mematine (namenda); neuronal loss
recreationally used dopaminergic agonists
cocaine, amphetamine, methamphetamine
medically prescribed dopaminergic agonists
- dextroamphetamine (Adderall)
- methylphenidate (Ritalin)
- L-dopa
dopamine antagonists that are medically prescribed for schizophrenia & drug-induced psychosis include ___
- Thorazine
- Hadol
- Clozaril
- Abilify, Aripiprex
indigenous people of ___ have chewed coca leaves to ___
Peru; increase their stamina in the harsh environment & high elevations where they live
crack is chemically altered so that it ___
vaporizes at low temperatures, then the vapors are inhaled
refined cocaine powder can either be ___
sniffed (snorted) or injected
who popularized cocaine in the late 1800s as an antidepressant
Sigmund Freud
how is cocaine a local anesthetic?
it reduces a cell’s permeability to sodium ions and so reduces nerve conduction
synthetic compound that increases the neurotransmitter dopamine in the synaptic cleft by reversing the dopamine transporter
amphetamine
how does amphetamine work as a dopamine agonist?
prevents dopamine reuptake by reversing the direction of the transporter, allowing dopamine to continue to interact with postsynaptic D2 receptors
how does Thorazine work as a dopamine antagonist?
occupies site on D2 receptor
how was the synthetic compound amphetamine discovered?
thru attempts to synthesize the CNS transmitter epinephrine, which also acts as a hormone to mobilize the body for fight or flight in times of stress
difference between amphetamine and cocaine (both dopamine agonists)
- amphetamine reverses dopamine reuptake transporter
- cocaine blocks transporter
___ was originally used to treat asthma and sold as inhalers thru the 1940s
benzedrine (a form of amphetamine)
___ was widely used in WWII to help troops and pilots ___
amphetamine; stay alert, increase confidence/aggression, boost morale
what is amphetamine marketed as today?
a weight-loss aid
lifetime prevalence of methamphetamine use in the US once estimated to be as high as __
8%
___ are medically prescribed to treat ADHD, and the recreational dosage of both is ___ higher than the medically prescribed dosage
amphetamine (adderall) and methylphenidate (ritalin); 50x
chronic recreational use of amphetamine (Adderall) and methylphenidate (Ritalin) can lead to ___
psychosis
idea that excess dopamine activity (esp. in frontal lobes) causes symptoms of schizophrenia
dopamine hypothesis of schizophrenia
since 1955, when dopaminergic antagonists (antipsychotics) were introduced into therapeutic use, resident populations w/ schizophrenia in mental hospitals have ___
decreased dramatically
incidence of schizophrenia
1 in 100
___ of those who are homeless and ___ of incarcerated people have mental health issues
75%; 50%
___ as many mentally ill people were incarcerated vs. resided in mental institutions
10x
first-generation antipsychotics (FGAs) include drug classes ___, and act mainly by ___
phenothiazines + butyrophenones; blocking the dopamine D2 receptor, reducing motor activity + alleviating the excessive agitation of people w/ schizophrenia
second-generation antipsychotics include ___ and work by ___
clozapine; blocking dopamine D2 receptors + blocking serotonin 5-HT2 receptors
long-term use of D2 antagonists can produce unwanted side effects like ___, which is ___
tardive dyskinesia (TD); a movement disorder that results in involuntary, repetitive body movements such as grimacing, sticking out the tongue, smacking the lips, rapid jerking movements, or slow writhing movements
most serotonergic agonists also have ___ activity
adrenergic
serotonergic agonists are well known for ___
altering perceptions of one’s surroundings, feelings, sensations and images (trips)
serotonergic agonist examples
natural: mescaline, DMT, psilocybin
synthetic: LSD, MDMA
good trips on serotonergic agonists can be pleasurable and are associated with ___
- feelings of joy/euphoria
- disconnection from reality
- decreased inhibitions
- belief that one has extreme mental clarity/superpowers
bad trips on serotonergic agonists are associated with ___
- irrational fears
- panic attacks
- paranoia
- rapid mood swings
- intrusive thoughts of hopelessness
- wanting to harm others
- suicidal ideation
repeated use of serotonergic agonists can lead to problems with ___, and currently these recreational drugs are ___
sleep, mood, memory; illegal
__ of the adult US population has major depression at one time
6%
major depression is diagnosed in ___ as many women as men
twice
in the course of a lifetime, ___ of US adults may have at least one episode of major depression that lasts for months or longer
30%
factors attributed to depression
- inadequate nutrition
- stress from difficult life conditions
- acute changes in neuronal function
- damage to brain neurons
3 different types of serotonergic agonist drugs prescribed for depression
- monoamine oxidase (MAO) inhibitors
- tricyclics
- selective serotonin reuptake inhibitors (SSRIs)
drug that blocks the enzyme monoamine oxidase from degrading such neurotransmitters as 5-HT, NE and DA
monoamine oxidase (MAO) inhibitors
drug, characterized by its three-ring chemical structure, that blocks 5-HT reuptake transporter proteins
tricyclics
drug that blocks 5-HT reuptake into the presynaptic terminal and most commonly used to treat depression
selective serotonin reuptake inhibitors (SSRIs)
why do antidepressants take weeks to develop?
they stimulate second messengers in neurons to activate the repair of neurons damaged by stress
___ increases the production of new neurons in the hippocampus
Prozac (SSRI)
most people recover from depression within ___ of its onset
1 year
of all psychological disorders, ___ is one of the most treatable
major depression
since the 1950s, depression has been treated with:
- serotonergic drugs
- cognitive-behavioural therapies (CBTs)
- electroconvulsive therapy (ECT)
___ can be an acute treatment for patients with major or bipolar depression who are at risk for suicide
ketamine
several studies show ___ in the suicide rate between children/adolescents who receive SSRIs vs. a placebo
no difference
why do 20% of patients with depression fail to respond to antidepressant drugs?
depression can have many causes that are not treatable by serotonin agonists
side effects of antidepressants
- increased anxiety
- sexual dysfunction
- sedation
- dry mouth
- blurred vision
- memory impairment
any endogenous or exogenous compound that binds to opioid receptors to produce morphine-like effects
opioids
3 sources of opioids
- isolated (morphine, codeine)
- altered (heroin, oxycodone)
- synthetic (fentanyl, methadone)
2 properties of opioids
- sleep-inducing (narcotic)
- pain-relieving (analgesic)
5 classes of opioid peptides
- dynorphins
- enkephalins
- endorphins
- endomorphins
- nociceptin
4 receptors on which each opioid peptide binds to
- delta
- kappa
- mu
- nociceptin
___ most closely mimics endomorphins and binds most selectively to the __ receptors
morphine; mu
a white milky latex extracted from the seed pods of the poppy, Papaver somniferum
opium
___, whose primary ingredient is morphine, has been used for thousands of years to produce euphoria, analgesia, sleep, and relief from diarrhea/coughing
opium
which chemist isolated two chemicals from opium, codeine and morphine, in 1805?
Friedrich Sertürner
___ is often an ingredient in prescription cough medicine/pain relievers - the liver has an enzyme that converts it to morphine
codeine
a portion of blond-haired and blue-eyed people lack this enzyme
the enzyme that converts codeine to morphine
___ alters our perception of pain
morphine
semi-synthetic opioids, such as heroin and oxycodone, affect __ receptors
mu
___ is more potent & fat-soluble than morphine and penetrates the blood-brain barrier more quickly, allowing it to produce very rapid but shorter-acting psychoactive affects
heroin
all opioids are potently ___, and ___ is at a crisis point worldwide
addictive; abuse of medically prescribed opioids
opioid ingestion produces wide-ranging physiological changes in addition to:
altering pain perception, including relaxation and sleep, euphoria, and constipation
physiological effects of opioid ingestion
- respiratory depression (primary cause of death)
- decreased blood pressure
- pupil constriction
- hypothermia
- drying of secretion
- reduced sex drive
- flushed, warm skin
the term “cold turkey” is a reference to
the cold skin that accompanies opioid withdrawal, in which the hair stands up and looks like turkey skin
because opioid use results in both tolerance and sensitization, an opioid user is at constant risk of ___
overdosing
in the US and Canada, opioid overdose is currently the ___ cause of death in people under 50
1
drugs used to treat overdoses and opioid addiction
competitive inhibitor
a competitive inhibitor which acts quickly to block opioid action by competing with the opioid for binding sites
naloxone
because they can also be long-acting, ___ can be used to treat opioid addiction after the addicted person has recovered from withdrawal symptoms
competitive inhibitors
one of the objectives of pain research
producing an analgesic that does not produce addiction
what country does not treat chronic pain with opioids, avoiding the opioid crisis?
Japan
___ alters mood primarily by interacting with the CB1 receptor on neurons and the CB2 receptors on glial cells/other body tissues
tetrahydrocannabinol (THC)
cannabis has ___ toxicity, ___ have died from an overdose, but may have a detrimental effect on ___ and positive effect on ___
extremely low; 0 people; mood & memory; mental overload
what term fed into a growing racism and xenophobia against Mexicans?
marijuana
the 2 endogenous molecules our body produces that bind to CB1 and CB2
anandamide + 2-AG
___ reduces anxiety, enhances forgetting, may prevent the brain’s memory systems from being overwhelmed by all the information to which we are exposed each day
anandamide
___ relieves nausea and emesis (vomiting) in patients undergoing cancer chemotherapy who are not helped by other treatments & stimulates the appetite in patients with anorexia-cachexia (wasting) syndrome
cannabis
cannabis has also proved useful for treating:
- glaucoma (increased pressure in eye)
- spastic disorders like MS
- disorders associated w/ spinal cord injury
- some epilepsy syndromes
many people self-prescribe cannabis for a wide range of ailments including ___
PTSD
___ hamper scientific investigation into cannabis’ useful medicinal effects
legal restrictions
alcohol is linked to many harmful behaviours like:
- unprotected sexual activity
- driving while intoxicated
- date rape
- spousal/child abuse
- aggressive behaviours
- crime
explanations for the effects of alcohol
- disinhibition
- learning
- behavioural myopia
explanation holding that alcohol has a selective depressant effect on the brain’s frontal cortex, which controls judgement, while sparing subcortical structures responsible for more instinctual behaviours, such as desire
disinhibition theory
___ depresses learned inhibitions based on reasoning and judgement while releasing the “beast” within
alcohol
who questions disinhibition theory in their book Drunken Comportment, citing many instances in which behaviour under the influence of alcohol changes from one context to another
Craig MacAndrew and Robert Edgerton
MacAndrew and Edgarton suggest that behaviour under the effects of alcohol is ___
learned
“nearsighted” behaviour displayed under the influence of alcohol, wherein local and immediate cues become prominent; remote cues and consequences are ignored
behavioural myopia
in an altercation, a person with ___ will be quicker than usual to throw a punch because the fight cue is so strong and immediate
behavioural myopia
___ can explain many lapses in judgement that lead to risky behaviour
behavioural myopia
approx. ___ of North Americans smoke
25%
a pattern of drug use in which people rely on a drug chronically and excessively, allowing it to occupy a central place in their life
substance abuse
a complex brain disorder characterized by escalation, compulsive drug taking, and relapse; called substance use disorder per the DSM-5
addiction
3 characteristics of additions
- escalation
- compulsive drug taking
- relapse
___ refers to increased drug consumption through increased dose or dosing frequency
escalation
___ is a critical factor in the transition from sporadic use to the compulsive and relapsing drug use that characterizes addiction
escalation of drug use
repetitive and persistent drug administration despite negative consequences
compulsive drug taking
___ involves the recurrence of compulsive drug use after a period of abstinence
relapse
addictive drug use is marked by:
- inordinate time spent seeking, preparing, and consuming drugs at the expense of everyday responsibilities
- numerous failed attempts at abstinence
physical and psychological behaviour displayed by a user when drug use ends
withdrawal symptoms
withdrawal symptoms include
- muscle aches and cramps
- anxiety attacks
- sweating
- nausea
- convulsions and death
symptoms of alcohol or morphine withdrawal can begin ___ and tend to ___ before they subside
within hours of the last dose; intensify over several days
___ illustrates that the power of psychological dependence can be as influential as the power of physical dependence
smoking cigarettes
one does not suffer severe withdrawal symptoms if deprived from cigarettes, but can display
irritability, anxiety, increased appetite and insomnia
the common property many addictive drugs (dopaminergics, GABAergics, opioidergics) have
they produce psychomotor activation
increased behavioural and cognitive activity so that at certain levels of consumption, the drug user feels energetic and in control
psychomotor activation
psychomotor activation led to the hypothesis that all abused drugs act on this same target in the brain
the dopaminergic pathway from the ventral tegmental area to the nucleus accumbens
___ are associated with an increased risk of drug initiation and drug addiction; includes abuse, neglect, mental illness of house member, witnessing violence against mother, substance abuse by house member, parental separation, incarceration of a house member
adverse childhood experiences (ACEs)
each ACE (adverse childhood experience) increases the likelihood for early drug initiation by a factor of ___
2-4
compared to people with 0 ACEs (adverse childhood effects), people with ___ ACEs have been found to be 7-10x more likely to report drug use problems and addictions
5 or more
data collected over 4 generations suggests that the effects of these ACEs ___ be accounted for by increased availability of drugs, changing social attitudes toward drugs, or recent massive expenditures and public information campaigns to prevent drug use
cannot
___ of individuals who have experienced 5+ ACEs have not become addicted to drugs
90%
women are ___ sensitive to drugs as men, on average, due in part to ___
2x more; smaller size + hormonal differences
women have ___ incidences of drug addiction vs men
more
the central problem with hedonia hypothesis
the initial pleasurable experience wears off w/ repeated drug taking & can become aversive, yet the user continues to take the drug
hedonia hypothesis
the pleasurable “rush” associated with natural experiences lead to a variety of impulse control disorders (overeating, gambling, repeated drug use)
the brain circuits are ___ for pleasure (liking) and repeating behaviours (wanting)
different
explanation holding that when a drug is associated w/ certain cues, the cues themselves elicit desire for the drug (AKA incentive sensitization theory)
wanting-and-liking theory
who defined wanting as craving, whereas liking is the pleasure the drug produces?
Terry Robinson and Kent Berridge
with repeated use, ___ for “liking” develops, and the expression of “liking” ___
tolerance; decreases
with repeated use, “wanting” ___, and craving ___
sensitizes; increases
the decision to take a drug is made in the ___, an area that participates in most daily decisions
prefrontal cortex
when a drug is taken, it activates ___ that are generally related to pleasurable experiences
endogenous opioid systems
wanting drugs may spring from activity in the ___
nucleus accumbens of the dopaminergic activating system
in mesolimbic pathways, the axons of dopamine neurons in the midbrain project to these structures
- basal ganglia
- nucleus accumbens
- frontal cortex
- allocortex
___ is the neural correlate of wanting and the repetition of behaviour
dopamine release
who proposes that the repeated pairing of drug-related cues to drug-taking forms neural associations (learning) in the dorsal striatum, resulting in a habit (unconscious)
Barry Everitt
Barry Everitt proposes the repeated pairing of drug-related cues to drug taking forms ___ in the ___, a region in the basal ganglia consisting of ___
neural associations (learning); dorsal striatum; caudate nucleus + putamen
drug users lose control of decision related to drug taking, and ___ gives way to the craving of addiction
the wanting - the voluntary control over drug taking
the desire for a drug is often greatest when ___
the addicted person is maximally high, NOT during withdrawal
___ strongly influence decisions to take or, continue taking, a drug
cues associated with drug taking:
- social situation
- sight of drug
- drug paraphernalia
rats becoming conditioned to cues with reinforcement, and other animals are attracted to the location where they receive reinforcement exemplifies
there may be at least 2 types of addiction
the similarities between exaggerating normal behaviours and drug addiction suggest ___
they depend on the same learning and brain mechanisms
3 lines of evidence suggesting a genetic contribution to differences in drug use
- if a twin abuses alcohol, their identical twin is more likely to be it than would a fraternal twin
- people adopted shortly after birth are more likely to abuse alcohol if their biological parents were alcoholic
- although most animals do not care for alcohol, selective breeding of mice, rats and monkeys can produce strains that consume large quantities of it
addictive drugs may reduce the transcriptional ability of genes related to ___ and increase the transcriptional ability of other genes related to
voluntary control; behaviours susceptible to addiction
___ can account for both the enduring behaviours that support addiction and for the tendency of drug addiction to be inherited
epigenetics
two most used drugs
alcohol and tobacco
two drugs that carry the harshest penalties
cocaine and heroin
in the US, the ___ made heroin and a variety of other drugs illegal and made the treatment of addicted people by physicians in their private offices illegal
Harrison Narcotics Act of 1914
the ___ partly reversed the Harrison Narcotics Act of 1914, allowing the treatment of addicted patients but with a number of restrictions
Drug Addiction Treatment Act of 2000
tobacco has ___ proven health risks than cannabis
much higher
moderate use of alcohol is likely ___, while moderate use of opioid is likely ___
benign; impossible
drug addiction must be treated in the same way as ___
chronic behavioural addictions and medical problems
MSG and glutamate-like substances, like domoic acid and kainic acid, has been found to ___ neurons
kill
some drugs, such as PCP ketamine, which act as glutamate agonists, cause neuronal ___
death
heroin addicts who developed Parkinson disease after using ____
synthetic heroin laced with a contaminant (MPTP)
in low doses, methamphetamine ___
- elevates mood
- increases alertness, concentration, energy
- reduces appetite, promotes weight loss
at high doses, methamphetamine ___
- induces psychosis in vulnerable individuals
- can cause seizures + brain hemorrhage
individuals who compulsively take methamphetamine, like L.V., display ___
- unpredictable/rapid mood swings
- paranoia
- hallucinations, delirium, delusions
- often violent behaviour
chronic methamphetamine use has a toxic effect on ___, leading to ___ in several brain regions and ___
human midbrain dopaminergic neurons + serotonin neurons; reductions in grey-matter volume; adverse changes in markers of metabolic integrity
although ___ is structurally related to amphetamine, it produces hallucinogenic effects, therefore called a hallucinogenic amphetamine
MDMA/Molly/Ecstasy
doses human users take of MDMA result in the degeneration of___
very fine serotonergic nerve terminals
___ use may cause memory impairments
MDMA
MDMA may contain a contaminant called ___, which is often called Dr. Death because ___
paramethoxymethamphetamine (PMMA); the difference between a dose that causes behavioural effects vs. a dose that causes death is miniscule
___ use is related to the blockage of cerebral blood flow + other changes in blood circulation
cocaine
psychoactive properties of cocaine are similar to those of ___, so it is also suspect regarding ___
amphetamine; brain damage
THC may trigger psychosis in vulnerable individuals, but there is no evidence that it will result in ___
brain damage
recent studies suggest that ___ may have neuroprotective properties, like ___
THC; aid brain healing after TBI, slow the progression of diseases associated with brain degeneration including Alzheimer + Huntington disease
many hormones operate in a ___ that includes the brain and body
feedback system
the hypothalamus produces neurohormones that stimulate the ___ to secrete hormones into the circulatory system, which influence the remaining ___ to release appropriate hormones into the bloodstream to act on various targets in the body & send feedback to the brain
pituitary gland; endocrine glands
in addition to influencing sex organs + physical appearance, hormones affect ___
neurotransmitter function, especially in neurons that influence sexual development and behaviour
how do hormones influence gene expression?
they bind to special receptors then are transported to the nucleus to influence transcription, which influences the synthesis of proteins
fat-soluble chemical messenger synthesized from cholesterol
steroid hormones
as many as ___ hormones are classified as either steroids or peptides
100
testosterone and cortisol are ___ hormones
steroid
how to steroids work?
- diffuse away from their site of synthesis in the glands (incl. gonads, adrenal cortex, thyroid)
- bind to steroid receptors on cell membrane/in the cell
- frequently act on cellular DNA to influence gene transcription
chemical messenger synthesized by cellular DNA that acts to affect the target cell’s physiology
peptide hormones
insulin, growth hormone, and endorphins are ___ hormones
peptide
how do peptide hormones work?
- bind to metabotropic receptors on cell membrane
- generates a second messenger that affects cell’s physiology or gene transcription
3 main functional groups steroid + peptide hormones fall into regarding behaviour
- homeostatic hormones
- gonadal (sex) hormones
- glucocorticoids
one group of hormones that maintain internal metabolic balance + regulate physiological systems in an organism
homeostatic hormones
___ control both the concentration of water in blood/cells & the levels of sodium, potassium, + calcium in the body, and promote digestive functions
mineralocorticoids (e.g., aldosterone)
one group of hormones that control reproductive functions + bestow sexual appearance/identity as male or female
gonadal (sex) hormones
what gonadal hormones control the menstrual cycle?
estrogen + progesterone
what gonadal hormones control the release of breast milk?
prolactin + oxytocin
one group of steroid hormones secreted in times of stress; important in protein + carbohydrate metabolism
glucocorticoids
cortisol and corticosterone are classified as ___
glucocorticoids
normal glucose concentration in the bloodstream varies between ___
80-130mg per 100mL of blood
what happens when there is increased glucose in the blood?
- pancreas releases insulin, which instructs the enzyme glycogen synthase in liver
- muscle cells start storing glucose as glycogen
- resulting decrease in glucose decreases stimulation of pancreatic cells, which stops insulin production, halting glycogen storage
what happens when the body needs glucose for energy?
glucagon (liver hormone) stimulates the enzyme glycogen phosphorylase to initiate glucose release from its glycogen storage site
___ is cause by a failure of the pancreatic cells to secrete any or enough insulin - as a result, blood sugar levels can rise or fall
diabetes mellitus
in hyperglycemia, blood sugar levels ___ because ___, resulting in ___
rise; insulin doe snot instruct the body cells to take up glucose; failure of cell function through glucose starvation
chronic high blood glucose levels can cause damage to the ___
eyes, kidneys, nerves, heart, and blood vessels
in hypoglycemia, ___ can lead to __ blood sugar severe enough to cause fainting
inappropriate diet; low
who proposed insulin resistance in brain cells may be related to Alzheimer disease?
Eric Streen
hunger/eating are influenced by many homeostatic hormones, including ___
leptin + ghrelin
___ is secreted by adipose (fat) tissue, inhibits hunger, and is called the satiety hormone
leptin
___ is secreted by the GI tract when the stomach is empty, regulates growth hormones, energy use, and induces hunger
ghrelin
leptin + ghrelin act on receptors on the same neurons of the ___ of the hypothalamus and so contribute to energy homeostasis by ___
arcuate nucleus; managing eating
class of synthetic hormones related to testosterone that have both muscle-building and masculinizing effects
anabolic steroids
in steroids, anabolic refers to ___ and androgenic refers to ___
muscle-building; masculinizing
Russian weight lifters were the first to use ___ in 1952 to enhance performance and win international competitions
anabolic steroids
the use of anabolic steroids is ___ among athletes and nonathletes
equal
anabolic steroid use in high schools may be as high as __ for males and __ for females
7%; 3%
risks associated with anabolic steroid use
- reducing body manufacture of testosterone
- reduces male fertility + spermatogenesis
- increase in muscle bulk + aggression
- increased risk of heart attack/stroke + tumors
- compromised liver + kidney function
- enhanced male-pattern baldness
- (female) acne, enlarged clitoris, increased body hair, deepend voice
approved clinical uses for anabolic steroids
- treats hypogonadal males
- treats muscle loss subsequent to trauma
- recovery of muscle mass in malnourished ppl
- (female) endometriosis + fibrocystic disease
a ___ is a stimulus that challenges the body’s homeostasis + triggers arousal
stressor
the body’s response is ___ if a stressor is exciting, sad, or frightening
the same
fast-acting stress pathway
- fight or flight: hypothalamus sends a neural message thru the spinal cord
- sympathetic division of the ANS stimulates the medulla of the adrenal gland
- adrenal medulla releases epinephrine into the circulatory system
- epinephrine activates the body’s cells, endocrine glands, and the brain
slow-acting stress pathway
- hypothalamus releases CRH (corticotropin-releasing hormone) into pituitary gland
- pituitary gland releases ACTH, which acts on the cortex of adrenal gland
- adrenal cortex releases cortisol into circulatory system
- cortisol activates the body’s cells, endocrine glands, and the brain
what happens if the stress response is not shut down?
- body continues to mobilize energy at the cost of energy storage
- proteins are used up, resulting in muscle wasting/fatigue
- growth hormone is inhibited so the body cannot grow
- GI system remains shut down, reducing the intake/processing of nutrients to replace used resources
- reproductive functions are inhibited
- suppressed immune system = possibility of infection/disease
why does Sapolsky think the hippocampus plays an important role in turning off the stress response?
- contains a high density of cortisol receptors
- axons project to hypothalamus
- well suited to detecting cortisol in blood + instructing hypothalamus to reduce blood cortisol levels
why does Sapolsky think the hippocampus plays an important role in turning off the stress response?
- contains a high density of cortisol receptors
- axons project to hypothalamus
- well suited to detecting cortisol in blood + instructing hypothalamus to reduce blood cortisol levels
who observed wild-born vervet monkeys in Kenya that died of a syndrome related to stress?
Sapolsky
explain the vicious circle
- unrelieved stress promotes excessive release of cortisol = damages hippocampal neurons
- damaged neurons cannot detect cortisol = cannot signal adrenal gland to stop producing
- resulting feedback loop enhances cortisol secretion, further damaging hippocampal neurons
stress response circuits in ___ are similar to those in humans
rats + monkeys
stress-induced hippocampal damage is postulated to result in ___, while stress-induced amygdala changes are postulated to result in ___
impaired memory; increased emotional responses
research on women who were sexually abused in childhood and have PTSD yield some reports of changes in ___
memory or hippocampal volume
why has research not yet determined whether the cumulative effects of stress can damage the hippocampus?
- uncertain how much damage to the hippocampus must occur to produce a stress syndrome
- brain-imaging techniques may not be sensitive to subtle changes in hippocampal cell function or to moderate cell loss
- wide individual and environmental differences influence how people respond to stress
- neonatal stress can influence hippocampal neurogenesis
- humans are long lived + gather many experiences that complicate a single stressful event
who reported that the density of glucocorticoid receptors in the people who committed suicide/had been sexually abused as children was lower than both controls + suicide victims who had not been abused?
Patrick McGowan
what does the decrease in receptors and in glucocorticoid mRNA suggest about childhood abuse?
it induces epigenetic changes in the expression of glucocorticoid genes
What does Patrick McGowan’s study suggest?
there’s a mechanism thru which stress can influence hippocampal function without necessarily being associated with a decrease in hippocampal volume
