Brain Anatomy & Physiology Neurotransmitters

Question 1

What is a neurotransmitter?

Answer 1

A neurotransmitter is a chemical substance released from the vesicle of a pre-synaptic neuron to the receptors in the post synpatic neuron to transfer a signal.

Question 2

Describe the seven processes of Neurotransmitter action

Answer 2

1. Neurotransmitters molecules are synthesized from precusors under the influence of enzymes
2. Neurotransmitter molecules are stored in vesicles
3. Neurotransmitter molecules that leak from their vesicles are destroyed by enzymes
4. Action potential causes vesicles to fuse with the presynaptic membrane and release their neurotransmitter molecules into the synapse
5. Released neurotransmitter molecules bind with autoreceptors and inhibit subsequent neurotransmitter release
6. Released neurotransmitter molecules bind to post synaptic receptors
7. Released neurotransmitter molecules are deactivated by reuptake or enzymatic degradation

Question 3

Explain agonistic drug effects

Answer 3

1. The drug increases the synthesis of the neurotransmitter molecules (eg: by increasing the amount of the precursor)
2. Drug increases the number of neurtransmitter molecules by destroying degrading enzymes
3. Drug increases the release of neurotransmitter molecules from terminal buttons
4. Drug binds to auto receptors and blocks their inhibitory effect on neurotransmitter release
5. Drug binds to presynaptic receptors and either activates them or increases the effect of them of neuortransmitter molecules
6. Drug blocks the deactivation of neurotransmitter molecules by blocking degradation or reuptake

Question 4

Explain antagonist drug effects

Answer 4

1. Drug blocks the synthesis of neurotransmitter molecules (eg: destroys synthesised enzymes)
2. Drug causes the neurotransmitter molecules to leak from the vesicles and be destroyed by degrading enzymes
3. Drug blocks the release of the neurotransmitter molecules from terminal buttons
4. Drug activates autoreceptors and inhibits neurotransmitter release
5. Drug is a receptor blocker, it binds to the post synaptic receptor and blocks the effect of the neurotransmitter

Question 5

Name 4 essential neurotransmitters

Answer 5

Dopamine
Serotonin
Glutamate
GABA

Question 6

Explain the role of serotonin

Answer 6

Serotonin is a type of neurotransmitter that is associated with different psychological and bodily functions such as mood, sexual desire, appetite, sleep and memory. If there are imbalances in the way serotonin is transmitted between neurons, through too much reuptake of this neurotransmitter, then this has implications for contributing to mood disorders such as depression.

Question 7

Explain the role of Selective Serotonin Reuptake Inhibitors (SSRI’s)

Answer 7

SSRI’s are a type of anti-depressant medication that work by increasing the amount of serotonin between cells. SSRI’s essentially aid in blocking the reuptake of serotonin into the presynaptic cell, meaning there is more serotonin left in the synaptic cleft. If there is more serotonin left in the synaptic cleft, it is more likely that serotonin will reach the receptors of the post synaptic cell.