Drugs of Dependence and Antidepressants Flashcards by Srishti D

What is drug dependence?

Drug taking becomes compulsive

Takes precedence over other needs

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What is drug abuse?

Use of illicit substances or illicit use of legal substances

Recurrent and clinically significant adverse consequences

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What contributes to psychological dependence?

Rewarding effect of psychoactive drug

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What is the rewarding effect of the psychoactive drug?

Positive reinforcement > desire to continue experience

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Does the rewarding effect only happen with drugs?

No, it can happen with any activity

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What contributes to physical dependence?

Habituation/adaptation

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What is habituation/adaptation?

Feeling normal/aversion of negative symptoms

Don’t take drug to feel good but not to feel bad

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What are the reward and salience circuits involved in drug abuse and addiction?

Nucleus accumbens

Ventral pallidum

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What are the memory and learning circuits involved in drug abuse and addiction?

Hippocampusw

Amygdala

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What are the motivational drive circuits involved in drug abuse and addiction?

Orbitofrontal cortex

Subcallosal cortex

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What are the inhibitory control circuits involved in drug abuse and addiction?

Prefrontal cortex

Anterior cingulate gyrus

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What happens to the inhibitory control circuits in drug abuse and addiction?

Removed to elicit excitation

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Which circuits have interplay between them in drug abuse and addiction?

Those for reward and salience, and memory and learning

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Which neurotransmitter is implicated in reward pathways, and how?

Increased dopamine in nucleus accumbens

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What are the key transmitters modulating dopaminergic transmission?

Atch
Serotonin
NA
GABA
Glutamate
Opioids

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Which neurotransmitters are targeted by most of the drugs that are used and abused?

Those that modulate dopaminergic transmission

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Describe the dose-response curve in the CNS

Bell-shaped rather than sigmoid

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What effects did cocaine have on people with high dopamine receptor levels?

Aversive effects

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What effects did cocaine have on people with low dopamine receptor levels?

Pleasant effects

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Do receptor levels change, and if so, what do they change in response to?

Yes, change in response to

Time
Disease
Drug taking

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How do some tolerance mechanisms work when receptors are involved?

Receptor levels are too high, so with extended drug use, they’ve been downregulated

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What are two examples of opioids?

Morphine

Heroin

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What are the CNS effects of opioids?

Euphoria

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What are two examples of CNS depressants?

Alcohol

Diazepam

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What are the CNS effects of CNS depressants?

Reduced anxiety

What are three examples of CNS stimulants?

Cocaine Amphetamine MDMA

What are the CNS effects of CNS stimulants?

Excitement Euphoria Reduce fatigue

What is an example of an hallucinogen?

LSD

What are the CNS effects of hallucinogens?

Altered perception

What is an example of a cannabinoid?

D-9-THC

What are the CNS effects of cannabinoids?

Altered perception

What is non-therapeutic drug use?

Consumption by choice not medical advice

What are the specific effects of CNS stimulants on CNS transmission>

NA, dopamine, and serotonin to various degrees

What does cocaine do at the synapse?

Block neuronal uptake of NA

What does amphetamine do at the synapse?

Utilises uptake carrier for NA to enter pre-synaptic terminal Displaces NA from synaptic terminal

What effect do cocaine and amphetamine have on NA at the synapse?

Increase NA levels in synaptic cleft

Which neurotransmitters are predominantly affected in the CNS by cocaine and amphetamine?

Dopamine | Serotonin

Which neurotransmitters does amphetamine release in the CNS?

Predominantly NA and dopamine | Also serotonin

With what do the effects of amphetamine vary?

Mood Personality Environment

What are the CNS effects of amphetamine?

Mood elevation and euphoria Increase locomotor activity Stereotypic behaviour

What effects does amphetamine have on physical and mental performance?

Fatigue postponed | Confident and speedy performance, but less accurate

What is the possible mechanism for the appetite suppressant activity of amphetamine?

Serotonin effect

What is a medical application of amphetamine?

Analogues used for ADHD

Does amphetamine induce tolerance?

Yes, need larger dose for same effect with long term use

What is the mechanism by which amphetamine induces tolerance?

Downregulation of receptors over time

Does amphetamine cause psychological dependence?

Yes, but not as marked as cocaine

Which group of people are more susceptible to amphetamine dependence?

Depressives | Lonely people

What are the physical withdrawal symptoms of amphetamine?

Lethargy Sleep Desire for food Depression

What does chronic use or an overdose with amphetamine cause?

``` Anxiety Nervousness Physically tension Tremors Confusion Dizziness Time passes quickly Hyperthermia Tachycardia Increased BP Vascular collapse > death Psychosis - hallucinations ```

Compared to amphetamines, what neurotransmitters do cocaine and MDMA targeet?

Target same ones but cocaine and MDMA have relative selectivity for dopamine, serotonin and NA

What are the cognitive effects of caffeine?

Increases alertness and well being No euphoria Delays onset of sleep

In what ways does caffeine stimulate mental activity?

Postpones boredom, fatigue, and inattentiveness | Enhanced intellectual and motor performance

What do high doses of caffeine cause?

Anxiety Tension Tremors

What is the drug class of caffeine?

Methylxanthine

What are the targets of caffeine?

Predominantly an adenosine antagonist Phosphodiesterase inhibitor > cAMP not broken down By targeting 2nd messengers, it affects transmission beyond NA, DA and 5-HT

Does caffeine cause dependence?

Not strongly in animals or humans | Reinforcing behaviour linked with social aspect

What is a withdrawal symptom of caffeine dependence?

Headache

What sort of hallucinations does LSD cause?

Visual Auditory Tactile - Sensory modalities get confused

What happens to your thought processes whilst on LSD?

Disturbed but aware drug-induced

Does LSD cause dependence?

Could be aversive rather than reinforcing some people - "bad trip"

How is tolerance to LSD mediated?

Receptor mediated

How fast does tolerance to LSD happen?

Quickly

What happens when you take LSD with other psychotomimetics?

Effects impaired by cross tolerance

What is the target of LSD?

In CNS agonist at 5-HT2 receptor | Causes inhibition of 5-HT neurons in Raphe

What neurotransmitters does MDMA/ecstacy release?

Dopamine and serotonin

What are the effects of MDMA?

Stimulant and hallucinogenic effects

Is MDMA as effective as amphetamine or LSD?

What cognitive effects does MDMA have?

Feeling of closeness Empathy Love Heightened self-awareness

Does MDMA cause dependence?

Yes because of rewarding reinforcing effect

What are the effects of MDMA on the cardiovasular system?

Increases HR | Increases BP

What effect does MDMA have on thermoregulation?

Disrupts it - causes chills and sweating

What is the effect of the active metabolites of MDMA on the brain?

``` Potential degeneration of 5-HT and DA neurons Affects - Mood - Memory - Sleep - Appetite ```

What effect do CNS depressants have?

Relaxation | Sense of well being

What are two forms of cannabis that are often taken?

``` Marijuana - Dried leaves - Flower heads Hashish - Extracted resin ```

What is the active component in cannabis?

D9-THC

What are the cognitive effects of D9-THC?

Relaxation Feeling of well being Sharpened sensory awareness - increased intensity of sounds and sights

What influences the effects of D9-THC?

Characteristics of drug | Individual

What are the cannabinoid receptors to which D9-THC binds?

CNS - CB1 | PNS - CB2

What type of receptors are CB1 and CB2, and what effect do they have when they're activated?

GPCRs | Inhibition of adenylate cyclase > inhibition of transmission

Which other drug can possibly interact with D9-THC?

Caffeine

What is anandamide?

Endogenous cannabinoid receptor agonist | Unknown physiological role

What is nabilone?

Synthetic cannabinoid analogue | Being developed as anti-emetic

What is the effect of cannabinoids on neurotransmitters?

Increase dopamine neuronal firing by decreasing GABAergic inhibition of dopamine neural activity

What are the central effects of D9-THC?

``` Impaired short term memory Impaired motor coordination Catalepsy Analgesia Anti-emetic Increased appetite ```

What are the peripheral effects of D9-THC?

Tachycardia Vasodilation Reduced intraocular pressure Bronchodilation

Does D9-THC cause dependence?

Some evidence of physical and psychological dependence in heavy users

What are the effects of ethanol on the neuron?

Inhibit Ca channel opening > stop exocytosis Enhance GABA action and glycine mediated inhibition - GABA-A receptors - Reversal by Flumazenil Opens some K channels > cell hyperpolarises Inhibits glutamate receptors - NMDA channel

How does ethanol bind to the GABA-A receptor?

Binds in lipid membrane Changes shape of receptor Increases GABA binding

What are the behavioural effects of ethanol?

Subjective - Increased self confidence - Euphoria - Usually loud and outgoing - Less often morose and withdrawn - At higher doses aggression and mood swings

What are the motor effects of ethanol?

Loss of motor coordination | Slurred speech

What are the tissue effects of ethanol?

Liver damage Neurodegeneration Foetal impairment

What is the mechanism of tolerance of ethanol?

Pharmacokinetic mechanism - enhanced clearance

What are the behavioural signs of ethanol withdrawal?

``` Anxiety Insomnia Nausea Anorexia Delusions Hallucinations ```

What are the neurological signs of ethanol withdrawal?

``` Tremor Hyperactive reflexes Agitation Delirium Convulsions Status epilepticus ```

What are some physical signs of ethanol withdrawal?

Vomiting Postural hypotension Sweating Hyperpyrexia

Drugs of Dependence and Antidepressants Flashcards

(95 cards)