Neurotransmitters 2

Question 1

What are the different types of neurotransmission?

Answer 1

Fast and slow

Excitatory and inhibitory

Question 2

Receptors for fast excitatory and inhibitory transmission?

Answer 2

ION CHANNEL-linked receptors

Question 3

Speed of fast transmission?

Answer 3

Milliseconds

Question 4

Process of fast transmission?

Answer 4

Neurotransmitters bind to receptors
Ion channels open
Ions move through the channels (can be in or out)
Effect is produced (excitatory OR inhibitory)

Question 5

Receptors for slow transmission?

Answer 5

G-protein coupled receptors

Question 6

Speed of slow transmission?

Answer 6

Seconds/minutes

Question 7

Process of slow transmission?

Answer 7

Transmitter binds with transmembrane receptor
G-protein in cytoplasmic region activates secondary messenger (e.g. cAMP cascade)
Secondary messenger greatly amplifies the effect

Question 8

2 excitatory ion channel-linked receptors and effects they cause?

Answer 8

Nicotinic cholinergic receptors - Na+ influx

Glutamate - Na+ influx

Question 9

3 inhibitory ion channel-linked receptors and effects they cause?

Answer 9

GABA - Cl- influx
Glycine - Cl- influx
5-hydroxytryptamino receptor - K+ efflux

Question 10

2 types of Glutamate receptors?

Answer 10

AMPA receptors

NMDA receptors

Question 11

Features of AMPA receptors?

Answer 11

Majority of fast excitatory synapses
Rapid onset, offset and desensitisation
Causes Na+ influx

Question 12

Features of NMDA receptors?

Answer 12

Slow component of excitatory transmission
Coincidence detectors which underly learning mechanisms
Causes Na+/Ca2+ influx, Ca2+ activates other pathways

Question 13

Glutamate removed by?

Answer 13

EEAT - excitatory amino acid transporter on presynaptic nerve terminal and glial cells

Question 14

Two fates of glutamate after stimulation?

Answer 14

Taken up into nerve terminal or glial cell
Repackaged into synaptic vesicles in nerve terminal
Converted to glutamine by glutamine synthetase in glial cells

Question 15

How are glutamate and GABA related and what catalyses the conversion?

Answer 15

Glutamate is a precursor to GABA, converted to GABA by glutamic acid decarboxylase

Question 16

2 fates of GABA after receptor binding?

Answer 16

Taken up into nerve terminal by GABA transporter and repackaged into synaptic vesicles or converted to SSA
Taken up into glial cell by GABA transporter and converted to succinate semi-aldehyde

Question 17

What is the GABA shunt?

Answer 17

Conversion of GABA to SSA in nerve terminal and entrance of resulting SSA in to the TCA cycle

Question 18

What is meant by the pentameric organisation of GABA receptors and why is this important?

Answer 18

5 domains

Pharmacologically important as different sites can be targeted by different drugs