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Yr 2 - Pharmacology > sedatives and anxiolytics > Flashcards

Flashcards in sedatives and anxiolytics Deck (86)
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1

What is a neurotransmitter?

A chemical substance released at the end of a nerve fibre by the arrival of a nerve impulse to another nerve fibre, muscle fibre or some other structure

2

What is an excitatory neurotransmitter?

Increases the probability that the target cell will fire an action potential

3

Give an example of an excitatory neurotransmitter:

Glutamate

4

What is an inhibitory neurotransmitter?

Decreases the probability that the target cell will fire and action potential

5

Give two examples of inhibitory neurotransmitters:

GABA (fast, found in virtually every part of the brain = short interneurones e.g. pain modulation)

Glycine (the inhibitory transmitter in the spinal cord)

6

Anxiety is a disorder of the...

CNS

Too few GABA = Anxiety

7

What was GABA first discovered as?

A product of microbial and plant metabolism

8

Which drug enhances the effects of GABA?

Valium

9

What causes epilepsy?

When GABA is lacking in certain parts of the brain

10

Where are there long GABAergic tracts to?

Cerebellum

Striatium

11

Which enzyme produces GABA?

Glutamic Acid Decarboxylase (GAD) -> found primarily in CNS

 

Co-enzyme = Vitamin B6

12

Which reaction produces GABA?

Glutamate -> GABA + CO2

13

How many isoforms of Glutamic Acid Decarboxylase are found in the brain?

Two

(GAD1 & GAD2 -> evolved separately but do same job!)

14

What is a glial cell?

A helper axillary cell = mop up and release neurotransmitter

15

What breaks GABA down?

GABA-Transaminase (GABA-T)

Co-factor = Vitamin B6= located in the mitochondria

16

What does GABA-T break GABA down into?

L-glutamate

17

Which drug is the most potent inhibitor of GABA-T?

Gabaculine (used more in lab than clinically)

18

What happens inside the cell after Gabaculine is given?

- Lots of GABA in cleft

- Eventually it stops vesicles containing GABA (relies on action of GAD to package produce GABA from glutamate and package into vesicle) = action potential = no release of GABA = no inhibition = Anxiety

19

Which cells express GABA receptors?

- Most neurones in the CNS

- Glial cells (astrocytes) = ANS neurones

20

When GABA binds what happens to the neurone?

Shift in membrane permeability to Chloride ions

 

postsynaptic inhibition = hyperpolarisation

presynaptic inhibition = depolarisation

21

How many types of GABA receptor are there?

What are they called?

Two

GABA-A & GABA-B

22

What type of receptor is GABA-A?

Ligand-gated ion (chloride) channel

23

What type of receptor is GABA-B?

GPCR

24

Which drug does GABA enhance the binding of?

Benzodiazepine

25

Why does GABA enhance binding of benzodiazepine?

GABA-A and Benzodiazepine (BDZ) receptor make up 2 separate parts of the same complex

26

Which is the most prevalent GABA receptor?

GABA-A

27

How many subunits does the GABA-A receptor have?

5 (pentameric)

N.b. subunit composition varies between brain regions and neuronal subpopulations (how we get sensitivity to specific regions)

28

Between which two subunits on the GABA-A receptor do benzodiazepines bind?

Alpha & Gamma

29

Which subunit of the GABA-A receptor binds GABA?

Alpha

30

Whats the birds eye view subunit arrangement for the GABA-A receptor?