5.3 Drugs Flashcards
Psychoactive drugs
naturally occurring or synthetic drugs that change a conscious experience
What can psychoactive drugs do to you?
- You can become tolerant to these drugs after prolonged usage
Definition of tolerance?
Reduction in effects experienced by the user
Definition of addiction?
compulsive usage despite negative consequences
What is an agonist?
a substance that mimics neurotransmitters
What is an antagonist?
A chemical or drug that binds to a receptor to prevent the binding of agonist
What do depressants do in low and high doses?
Generally slow CNS activity
Low: relaxation and sedation
High: slows down heart rate and brain activity
Examples of types of depressants?
Alcohol
Sedatives
Opiates
Facts about alcohol?
- The absorption rate depends on food in stomach and the body mass of the person
- alcohol increases the effect of GABA
- alcohol decreases the effect of glutamate
- Prolonged heavy drinking actually shrinks the brain
- There are health benefits with light use of alcohol
Facts on sedatives?
- benzodiazepines are the most common type of sedative
- Sedatives are taken to reduce anxiety, arousal, insomnia
- Sedatives act as GABA agonists (mimics GABA)
Facts on opiates?
- they mimic endogenous opiates
- Reduce pain, elevate mood, feelings of bliss/ euphoria
- derived from opium
- natural sources ( Morphine)
- partially synthetic sources (heroin)
- entirely synthetic (methadone, oxycodone,
hydrocodone) - high potential for abuse
What are stimulants?
They activate the nervous system and produce arousal
Types of stimulants?
- caffeine
- nicotine
- cocaine
- amphetamines
- ecstacy
Caffeine facts?
- coffee, tea, cocoa, soft drinks, energy drinks
- increased alertness, heart rate, loss of motor control, insomnia, nervousness
- physical dependence equals withdrawal symptoms common
Nicotine facts?
- from tobacco
- increased heart rate, respiration, feelings of arousal
- relaxes skeletal muscles
- EXTREMELY ADDICTED which means you can be highly tolerant and it has unpleasant withdrawal symptoms
- decreased life expectancy increased lung cancer risk
Cocaine facts?
- isolated from coca leaf
- increases availability of dopamine, serotonin, noradrenaline
- short-lived euphoria
- different forms ( smoke crack cocaine, injections)
- addictive
Amphetamine facts?
- synthetic
- long-lasting excitation of the sympathetic nervous system
- increase heart rate, motivation, elevates mood
- meth, Dexedrine, benzedrine (speed)
- used to treat ADHD
- long-term use - depression, paranoia, loss of bodily control, psychosis
Ecstacy (MDMA) facts?
- chemically similar to meth and hallucinogenic mushrooms, therefore a stimulant and mild hallucinogen
- Physiological arousal, mild hallucinogen
- “The love drug” feelings of affection, euphoria, connectedness
- neurotoxin
- can lead to long-term depression, cognitive defects, impulsivity
Types of hallucinogens?
- Marijuana
- LSD
What do hallucinogens do?
create distorted perceptions of reality ranging from mild to extreme
Marijuana facts?
- Cannabis sativa plant
- Tetrahydrocannabinol (THC)
- Endocannabinoid neurotransmitters
- changes perception of time and food
- No physical dependence, however psychological dependence is common
- memory impairment
- medical uses
LSD facts?
-Lysergic acid diethylamide - 25 or “acid”
- derived from the grain fungus ergot
- stimulates particular subtype of serotonin receptor
- increases glutamate in the cortex
- Profound effects on perception
- color perception, hallucinations, life-altering
experiences
Point of commonality?
There are similarities between all of these drugs in terms of they all have to do with dopamine
Dopamine
- an important role in mood and arousal
Especially positive mood - plays major role in reward-related behaviour
Dopamine as the point of commonality
- Mesolimbic dopamine (from midbrain to limbic striatum)
- ventral tegmental area (VTA) –> nucleus accumbens
(NAcc) - particular pathway where dopamine is most responsive to rewards ^
- Natural stimuli activate this track that stimulates dopamine but drugs can also activate this track if natural stimuli is not present
- Both natural stimuli and drugs of abuse activate mesolimbic dopamine
- Drugs of abuse bypass this sensory pathway:
- opiates: act on opioid receptors located on VTA cell bodies (reduce the amount of GABA)
- marijuana: acts on CB receptors in VTA
- cocaine/ amphetamine: ups the dopamine reuptake and reduces the dopamine release in the NAcc
A lot of these drugs increase dopamine which is why we like them
Others inhibit the inhibitor, GABA, which results in the flow of these neurotransmitters
- directly increases dopamine
- indirectly increases dopamine
Adaptation of dopamine?
- dopamine release to natural stimuli rapidly undergoes habituation
- drugs of abuse do not show within-session habituation BUT
- After chronic drug use, dopamine decreases in NAcc
- means craving
