Dopamine is a neurotransmitter released in some synapses in the brain - AQA - A-Level Biology - Question 7 - 2018 - Paper 1
Question 7
Dopamine is a neurotransmitter released in some synapses in the brain. The transmission of dopamine is similar to that of acetylcholine.
Dopamine stimulates the pro... show full transcript
Worked Solution & Example Answer:Dopamine is a neurotransmitter released in some synapses in the brain - AQA - A-Level Biology - Question 7 - 2018 - Paper 1
Step 1
Describe how.
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Answer
Dopamine attaches to receptors on the postsynaptic membrane. This interaction stimulates the entry of sodium ions into the postsynaptic neuron, leading to depolarization. The depolarization then initiates an action potential, allowing the neuron to transmit nerve impulses.
Step 2
Explain how.
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Answer
Morphine binds to opioid receptors located on presynaptic neurons. This binding can enhance the release of dopamine, which contributes to pain relief by increasing the overall level of dopamine in the neural synapses.
Step 3
Explain how this inhibits postsynaptic neurones.
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Answer
When GABA is released, it binds to receptors on the postsynaptic neuron, causing negatively charged chloride ions to enter. This influx of chloride ions makes the interior of the neuron more negative, resulting in hyperpolarization. Consequently, this prevents the neuron from reaching the threshold needed for depolarization and action potential, thereby inhibiting its activity.