Neurotransmitters

Question 1

What are the 4 criteria that a neurotransmitter needs to satisfy?

Answer 1

• It must be made in the presynaptic neuron
• It must be stored presynaptically in vesicles (exception is Nitric oxide - must be made on demand)
• It must be released on demand
• It must be inactivated

Question 2

How does inactivation of a neurotransmitter occur?

Answer 2

Diffusion

• easiest way to become ineffective;
• concentration is so low in the cleft that no neurotransmission occurs

Enzyme inactivation
- enzyme chops it up so it can’t interact with the post-synaptic membrane

Re-uptake
- diffuses, and is then re-uptaken by specialist pores to be used again later

Question 3

What are co-agonists?

Answer 3

Chemicals that prime/enhance receptors in terms of their response to a neurotransmitter
e.g.: Glutamate, Zinc, Glycine

Question 4

Summarise the classification of neurotransmitter by their structure

Answer 4

Amino acids - simple compound with a carboxyl group and an amino group

• Glutamate
• GABA
• Glycine

Biogenic Amines - comprising of two groups

• Catecholamines
• – Norepinephrine
• – Epinephrine
• – Dopamine
• Indolamines
• – Seratonin

Peptides

• Encephalin
• Endorphin
• Dynorphin