Exam Style 📖

Question 1

Neurons communicate with each other at the synapse. Discuss the events that occur leading to a message been passed from one neuron to another.
[5 marks]

Answer 1

•When an action potential arrives at the presynaptic terminal it causes the opening of voltage gated Ca?* channels and calcium enters the cell.
• Ca?* causes the vesicles to bind to the presynaptic membrane and neurotransmitter is released into the synapse by exocytosis.
. The neurotransmitter (e.g. dopamine) binds to receptors (e.g. D1 / D2 receptors) on the postsynaptic membrane.
The receptor
determines if an excitatory or inhibitory signal is passed on.
• The neurotransmitter is then broken down (e.g. by enzymes, COMT) or directly taken back up into the presynaptic terminal by transporters (e.g. dopamine transporter DAT) where it is

Question 2

Name the major excitatory and inhibitory neurotransmitters in the CNS?
[1 mark]

Answer 2

Excitatory:
- Glutamate
Extra: Epinephrine , Norepinephrine (go for glutamate)

Inhibitory:
- GABA

Question 3

Give 2 examples of how drugs can effect neurotransmission in the CNS.
[5 marks]

Answer 3

• Antipsychotics (atypical and typical) are used for the treatment of schizophrenia (e.g. olanzapine and haloperidol)

• Antagonists at Dopamine D2 receptors in the brain.

• 4 major dopamine pathways in the brain.

• Increase in dopamine leads to the positive symptoms in schizophrenia. Antipsychotics work (efficacy) by blocking the D2 receptor So dopamine cannot activate the receptor.

• Blocks D2 receptors throughout the brain - e.g. in the motor system - leads to extrapyramidal side effects.