3.1.2 recreational drugs Flashcards
what do recreational drugs do?
increase or decrease specific neurotransmitters at the synapse
they are substances taken for pleasure, usually working on the dopamine system
describe the reward pathway
The brain contains a ‘reward pathway’ which when activated causes us to experience pleasant and rewarding feelings, encouraging us to repeat the behaviour that activated the pathway and is a key component in learning
Being rewarded for specific behaviours has an adaptive function
Drugs hijack the reward system, producing pleasurable feelings without an adaptive function.
mode of action of heroin
- Hydrolyses into morphine which binds to opioid receptors in the reward pathway (NA) and the pain pathway.
- Reduces GABA activity (inhibits dopamine) leading to overactivity of dopaminergic neurotransmission in the reward pathways of the brain.
- This gives the same effect as having lots of endorphins released.
- Behaviour is affected: euphoria, pain relief.
Agonist
mode of action of nicotine
- Stimulates acetylcholine receptors which are associated with thinking, learning and alertness
- Binds to acetylcholine receptors causing the neuron to fire more frequently
- Indirectly affects the dopamine pathway increasing the amount of and speed of transmission of dopamine by blocking the enzyme which breaks it down
- Behaviour is affected: alertness, quicker reaction times, inhibited appetite
Agonist
mode of action of alcohol
Depressant effect on the nervous system and social control areas of the brain
Inhibits neural transmission by increasing the action of GABA (inhibitory neurotransmitter slows down messages such as noradrenaline, causing slower fight or flight responses) and reducing serotonin (associated with emotions - low mood)
Behaviour is affected: relaxed, confident but can develop into extreme behaviour such as aggression, slowed speech, less control of motor skills, dehydration, low mood
