Neurotransmitters

Question 1

Types of neurotransmitters

Answer 1

Amino acids = glutamate
Amines = dopamine, noradrenaline
Neuropeptide = endorphins

Question 2

How are neurotransmitters released?

Answer 2

Vesicles present in presynaptic and DOCK at the active zone
Super helix forms between presynaptic and vesicles
Calcium channels open upon AP and influx of Ca2+
Vesicles undergo conformational change = release NT

Question 3

Describe the action of neurological toxins

Answer 3

Tetanus = spastic paralysis = inhibit NT release
Botulinum = flaccid paralysis
Alpha latrotoxin = prevents recycling of vesicles but NT is still released

Question 4

Which 2 receptors are involved in neurotransmission?

Answer 4

Ion channel = FAST e.g. glutamate, GABA, Ach at nicotinic

G linked protein = SLOW e.g. Ach at muscarinic, dopamine

Question 5

Describe the glutamate synapse

Answer 5

• glutamate made by transamination
• binds to NMDA receptor and chases entry of sodium and calcium
• transporter on pre synaptic and glial cell (EAAT2 excitatory amino acid transporter 2) takes up left over glutamate
• glutamine syntetase inactivates glutamate —> glutamine

Question 6

What are the 2 glutamate receptors?

Answer 6

NMDA - needs 2 inputs , depolarisation and binding of glutamate
AMPA - fast synapses

Question 7

What is epilepsy ?

Answer 7

Regular fitting caused by abnormal release of glutamate

Question 8

Describe the inhibitory synapse GABA

Answer 8

Remove carboxyl group from glutamate = GABA (similar structure)
Glutamic acid decarboxylase = enzyme
When GABA binds to receptor = influx of cl-
Transporters take excess GABA up
GABA transaminase converts it into succinctness semialdehyde = enters TCA

Question 9

Drugs used to treat epilepsy

Answer 9

Valproate = affect GABA transporters and sodium channels
Phenobarbital = enhances GABA action 
Benzodiazepines = inhibitors GABA transporter