Recreational drugs

What is a drug?

• chemical affects way body works

• Drugs change message brain cells send each other

• Agonists: mimic neurotransmitter at receptor to strengthen its effects

• Antagonists: blocks normal activity of neurotransmitter at receptor

Strength of drugs

• knowledge of drugs grow, more addiction treatments

• Heroin (agonist) binds to opioid receptors - developed Naloxone (antagonist) blocks opioid receptors, works in reverse to tackle it, preventing dopamine release effect to help overcome addiction

Weakness of drugs

• social control

• May go against people’s wishes of treatment if gov forces it

What type of drug is cocaine

Agonist - mimics neurotransmitter at receptor to strengthen its effects

How to take cocaine

• snort

• Inject

How does cocaine work

• Attaches to terminal buttons at pre synaptic neuron to prevent re-uptake of DA

• Body keeps releasing DA in synapse leading to there to be excess dopamine in synapse

• Causes overstimulation at postsynaptic receptors

• = Intense pleasure / euphoria

What feelings does cocaine create

Pleasure, excitement, energises

What happens after repeated long term use of cocaine

• post synaptic neurons overstimulated and desensitisation happens

• Natural response to dopamine is lowered so want more cocaine to feel the same way

• Causes addiction - person motivated to take cocaine to feel the same way

Supporting cocaine

Nora Volkow et al

• PET scans track activity of DA transported during cocaine high

• Found that euphoria intensified as more DA transporters were occupied by cocaine

• Shows how cocaine causes euphoria by blocking re uptake of DA

Refuting cocaine

Volkow used PET scans

Bias as interpreting it is subjective

Lack accuracy + validity

What feeling does heroin produce

• sedative but still produces feelings of euphoria

What type of drug is heroin

Agonist - mimics endorphins to strengthen pain relief effect

How is heroin taken

• injected into vein

How does heroin work

• Heroin flows through bloodstream to brain

• Then broken down to morphine

• Morphine binds to normal opioid receptors at the synapse, releasing DA

• Has an extreme pain killing effect and binds longer than natural endorphins

Long term effect of heroin

• post synaptic receptors desensitised to heroin and are eventually desensitised to natural endorphins and morphine too

• Withdrawal occurs when haven’t taken heroin in a while causing pain as body cannot produce normal DA

• Addiciton therefore occurs to take it to feel well

Heroin supporting

Straiker and Mackie

• used hippocampal neurons from mice with human CB1 receptor to study effect of cannabis

• Found that mice with show similar addictive behaviours to humans when dosed with cannabis as excess DA found in neural pathway

• Therefore recreational drugs cause pleasant feelings

• Animals have similar synaptic transmission so can generalise

Heroin refuting

Animals not generalisable

Human brain more complex