NEUROTRANSMITTERS Flashcards
what is a neurotransmitter?
a chemical messenger that transmits signals across the synaptic gap between neurons
where are neurotransmitters stored and released from
stored in vesicles within presynaptic neuron and released into synaptic cleft during neurotransmission
what happens after a neurotransmitter is released?
it binds to a receptor site on the post synaptic neuron
EXCITATORY: triggers a new electrical
INHIBATORY: prevents new signal
what is reuptake?
when leftover neurotransmitters in the synaptic cleft are reabsorbed by the presynaptic neuron - stops the chemical message
what are excitatory neurotransmitters?
excitatory neurotransmitters increase the chance of a neuron firing - they stimulate brain
eg. Dopamine , glutamate
what are inhibitory neurotransmitters?
decrease the chance of a neuron firing - calm the brain and balance mood
Eg. GABA, serotonin
What is dopamine responsible for?
- reward and pleasure
- motivation
- addiction
- movement (too little is linked to Parkinson’s)
What is serotonin responsible for?
- mood regulation
- sleep
- appetite
Low levels linked to depression!!
What is GABA and its role?
Main inhibitory neurotransmitter!!
- reduces neural activity
- promotes calm and relaxation
Low levels linked to anxiety and epilepsy
Glutamate and its role
Main excitatory neurotransmitterQQ
- increases brain activity
- important for learning and memory
Too much= excitotoxicity (can damage neurons)
What is synaptic transmission process?
- Electrical impulse travels to axon terminal
- Vesicles release neurotransmitters into synaptic cleft during
- Neurotransmitters bind to receptors on the postsynaptic neuron
- Signal either passed on or blocked
- Excess neurotransmitters are broken down or reabsorbed (reuptake)
How do drugs affect neurotransmitters?
Drugs can:
- mimic neurotransmitters (agonists)
- block receptors (antagonist)
- increas release of neurotransmitters
- block reuptake, prolonging effects
What is an agonist drug?
A drug that imitates a neurotransmitter and activates receptors increasing its effect
What is an antagonist drug?
A drug that blocks neurotransmitter receptors, stopping them from binding
What neurotransmitter is involved in addiction?
Dopamine - addictive drugs increase dopamine in reward pathway creating pleasure and reinforcing use
What neurotransmitter is linked to depression?
Serotonin - low levels associated with low mood, irritability and sleep problems
What brain disorder in linked to dopamine imbalance?
Too little - Parkinson’s disease
Too much - schizophrenia
What is the reward pathway?
Brain circuit involving VTS and nucleus accumbens linked to dopamine - activated by rewards and addictive drugs
What happens when there is too much glutamate?
Excitotoxicity - overstimulation that can damage or kill neurons - linked to Alzheimer’s, stroke and seizures
How do neurotransmitters support biological explantations of behaviour?
Explain behaviour through chemical imbalances
- depression = low serotonin
- aggression = high dopamine, low serotonin
- anxiety = low GABA
Which study supports neurotransmitter - based explanations of aggression?
Raleigh et al. 1991 - studied monkeys
Low serotonin diets = more aggression
supports serotonins inhibitory role
Can neurotransmitter imbalances be inherited?
Yes - genetics can influence how much of a neurotransmitter is produces , how well it functions and how it’s reabsorbed
Linked to conditions like depression, ADHD, bipolar
Why is understanding neurotransmitters important in psychology?
Helps explain behaviour and mental illness
- supports biological treatments like SSRIs
- underpins neuroscience and drug therapy
