Drug Addiction Flashcards
Drug addiction
Chronic brain disorder
Compulsive drug seeking
Inability to stop using
Dependence on drug
Drug addiction is a disease that effects the _ system
Reward
Makes it hard to resist intense urges to take drugs
What is it called if there is a risk of return of a condition after treatment
Relapsing
How does conditioning relate to addiction?
People and places can become stimuli that make the addict feel compelled to use
Reinforcing
Objective
Something is reinforcing when an animal will perform a behaviour in order to obtain that stimulus.
Rewarding
Subjective
Often linked to euphoria which is a feeling of great happiness or well-being
Rewarding substances can lead to addiction
Psychological dependence
Craving
Compulsive drug use
Loss of control over intake
“addiction”
Physical dependence
When stopping a drug causes a withdrawal symptom
Tolerance
When continued use of a drug results in the need for increasing doses for equivalent effect
The cycle of addiction
Binge/intoxication –>
–> Withdrawal/negative effect –>
–> Preoccupation/anticipation –>
–> Binge/intoxication
Areas involved with binge/intoxication
Dorsal striatum
Ventral Tegmental Area
Cerebellum
Areas involved with withdrawal/negative effect
Basolateral amygdala (BLA)
Central amygdala (CeA)
Areas involved with preoccupation/anticipation
Prefrontal cortex (PFC)
Hippocampus
Which area did rats stimulate using ICSS?
Mesolimbic pathway
How much would rats stimulate the mesolimbic pathway?
Until death
What happened when the rats were given D1 or D2 antagonists (6-OHDA)
The rate of ICSS reduced
Role of D1 and D2 receptors
Both play a role in reinforcing stimuli and behaviours
D2 play a big role in addiction and people with fewer are predisposed to alcohol, cocaine or heroin
Where in rats brains were the D1 and D2 antagonists administered?
The nucleus accumbens
How does cocaine effect dopamine levels?
Blocks reuptake of neurotransmitter
Acts like SSRI
How do amphetamines effect dopamine levels?
Stimulates an excess to be released
Overwhelms reuptake process
Blocks transporter molecules involved with reuptake
How do opiates effect dopamine levels
Acts on µ-opioid receptors on GABAergic neurones.
Inhibits the GABA release, so it doesn’t inhibit dopamine release
Cause disinhibition of DA neurones in VTA.
How do cigarettes affect dopamine levels?
Acts on nicotinic acetylcholine receptors on DA neurons - increasing their firing rate
Another substance in the smoke blocks the action of MAO
How does cannabis (THC) effect dopamine levels?
Acts on cannabinoid receptors (CB1) on GABAergic neurons (Gi/o coupled)
Has inhibitory effect on GABA
Alcohol is a CNS _
Depressant
Effects of alcohol
Decreases after-hyperpolarization (AHP)
GABA A allosteric modulator (similar to benzodiazepines)
NMDA receptor antagonist
Calcium channel antagonist
Effects of alcohol decreasing AHP
AHP causes K channels to stay open for longer than Ca channels
This means it gets back to resting potential faster so that it can fire again
How does alcohol cause euphoria/pleasure?
Dopamine at opioid receptors
How does alcohol cause anxiolysis/ataxia?
Increased GABA
How does alcohol cause sedation/amnesia?
Increased GABA and decreased NMDA
How does alcohol cause nausea?
5HT3
How does alcohol cause neuroadaptation?
NMDA, 5HT
How does alcohol cause stress?
CRF
How does alcohol cause withdrawal
GABA, NMDA
Causing increased Ca and decreased Mg
