Lecture 8: GABA and glycine

Question 1

GABA comes from what via which enzymes?

Answer 1

Glutamate

GAD and Vit. B6

Question 2

Where is the rate limiting step of GABA synthesis?

Answer 2

GAD (enzyme) only found in cytoplasm containing GABA already.

Question 3

Inactivation of GABA?

Answer 3

Reuptake (Na dependent) to nerves and astrocytes

Metabolism via GABA-T and succinic semialdehyde dehydrogenase (to become succinate)

Question 4

What are the substrates in GABA metabolism?

Answer 4

GABA
succinic semialdehyde
succinate

Question 5

Pathways of GABA?

Answer 5

Mostly in interneurons

some long projections

Question 6

GABA functions?

Answer 6

INHIBITION

1. Cl- mediated hyperpolarisation (GABAa)
2. Decr. transmitter release via K+ (GABAb)

Question 7

Allosteric modulatory sites on the GABAa R?

Answer 7

Benzodiazepine (Incr. affinity to GABA and frequ. opening)

Barbituates (incr. duration of opening)

Question 8

What blocks benzodiazepine effects?

Answer 8

Flumazenil

Question 9

B-carbolines effect GABA action how?

Answer 9

Decrease it

Question 10

GABAb is what type of protein?

Answer 10

G-protein

Question 11

What is an agonist to GABAb?

Answer 11

Baclofen

Question 12

What is an antagonist to GABAb?

Answer 12

Phaclofen

Question 13

In the spinal cord, what is the main inhibitory NT?

Answer 13

Glycine

Question 14

Glycine is made from?

Answer 14

Serine

Question 15

Which cell does glycine originate from?

Answer 15

Renshaw Cells

Question 16

Strychnine-sensitive promotes what with glycine?

Answer 16

Inhibition

Question 17

Strychnine-insensitive promotes what with glycine?

Answer 17

excitation