GABA ☺️

Question 1

Describe the distribution and the characteristics of GABA

Answer 1

Widely distributed in CNS (30% of synapses)
Very little in PNS

AA

MOST IMPORTANT INHIBITORY NT IN CNS

Question 2

Describe the synthesis of GABA

Answer 2

Glutamate =(GAD)=> GABA

Question 3

Describe the storage of GABA

Answer 3

vGABAT (GABA 2H exchanger)

-H gradient driven by HATPase

Question 4

Describe the release of GABA

Answer 4

Ca dependent vesicular release at axon terminal

Question 5

Describe the receptors that respond to
GABA
-what drugs are clinically useful
-what are they used for

Answer 5

Ionotropic GABAa receptor anion channel
-Cl entry

Metabotropic GABAb to Gi, o

GABAa - benzodiazapine (agonist), propofol (anaesthetic)

GABAb - baclofen (agonist for alcohol withdrawal)

Question 6

Describe the reuptake of GABA

• what drugs are clinically useful
• what are they used for

Answer 6

GAT symport with Na into neurone or glia

Tiagabine (blocks GAT to treat epilepsy)

Question 7

Describe the degradation of GABA

• what drugs are clinically useful
• what are they use for

Answer 7

Mainly occurs in glia

GABA =(GABA transaminase)=> succinic semialdehyde

GABA transaminase also converts a oxoglutarate to glutamate

Vigabatrine (blocks GABAt in epilepsy treatment)

Question 8

What recreational drugs affect the GABA pathway

-could they be used clinically?

Answer 8

Barbiturates = anticonvulsant, sedatives
NO = analgesic

Question 9

How would you manage these conditions that are affected by the GABA pathway

• epilepsy
• anxiety
• insomnia
• muscle tone

Answer 9

Epilepsy => not enough GABA

Anxiety =>
-GABA agonists could be used as a sedative

Insomina => GABA can be used as a sedative

Muscle tone => GABA agonists can be used as muscle relaxants

GABA critical for CNS function