GABA

Question 1

What type of ions do GABAa receptors permit the influx of?

Answer 1

Chloride ions

Question 2

State the type of receptor GABAa is.

Answer 2

Ligand-gated ion channel

Question 3

Where is GABA synthesised?

Answer 3

Nerve terminals

Question 4

Which enzyme catalyses the reaction of GABA formation

Answer 4

Glutamate decarboxylase

Question 5

GABA is re-uptaken by which transporters?

Answer 5

GAT-1 and GAT-2

Question 6

What receptor type does GABAa activate?

Answer 6

Ligand gated ion channels

Question 7

What effect does GABA have?

Answer 7

Major inhibitory neurotransmitter

Question 8

Potential drug targets of GABA.

Give one example

Answer 8

Anxiety disorders.

Benzodiazepines: GABAa +ve allosteric modulators

Question 9

What is the precursor of GABA

Answer 9

Glucose

Question 10

The absence of which vitamin has an effect on GABA synthesis?
Why is this dangerous?

Answer 10

Vitamin B6 can lead to diminished GABA synthesis

Dangerous as it can lead to seizures due to the lack of neuroinhibitory drive.

Question 11

The steps of GABA synthesis

Answer 11

Glutamate
| (Glutamate decarboxylase)
| (Pyridoxal phosphate - Cofactor)
GABA

Question 12

How is GABA stored?

Answer 12

GABA = stored in oval vesicles

Question 13

How is GABA degraded?

Answer 13

GABA
 |  (GABA transaminase (GABA-T)
Succinic semialdehyde 
 | (Succinic semialdehyde dehydrogenase)
Succinic acid

Question 14

State the two types of neurotransmitter receptors

Answer 14

Ionotropic (Ligand-gated ion channels)

Metabotropic (GPCR)

Question 15

Give an example of an ionotropic and metabotropic receptor

Answer 15

Ionotropic: GABAa receptor
Metabotropic: GABAb receptor

Question 16

What effect do inhibitory neurotransmitters have on the membrane potential?

Answer 16

GABA causes HYPERpolarisation

Question 17

Why does hyperpolarisation occur?

Answer 17

Due to the efflux of K and influx of Cl

Question 18

Where in the brain are GABA projections?

What are they called?

Answer 18

In the cerebellum

Purkinje cells

Question 19

Which enzyme is responsible for converting glutamate to GABA

Answer 19

Glutamate decarboxylase

Question 20

Which GABA re-uptake transporter (GAT) subtype is predominantly expressed on neurons

Answer 20

GAT-1

Question 21

Which GABA re-uptake transporter subtype is predominately expressed on glial cells

Answer 21

GAT-3

Question 22

Which subunit interface comprises the GABAa receptor binding (for GABA)

Answer 22

Alpha and beta

Question 23

Which ions do GABAb receptor permit the efflux of?

Answer 23

K+

Question 24

GABAa receptor permits the influx of which type of ion?

Answer 24

chloride (Cl-) ions

Question 25

GABAa receptor functions as what type of receptor?

Answer 25

Ionotropic - Ligand gated ion channel

Question 26

Which enzyme is responsible for GABA breakdown?

Answer 26

GABA-T

GABA-transaminase