Drug Targets: Ligand Gated Ion Channels

Question 1

Nicotinic acetylcholine receptor (nAChR), are is an example of what type of receptors?

Answer 1

Ligand gated ion channel

Question 2

Structure of ligand gated ion channel

Answer 2

Pentameric structure
Each subunit has 4 membrane spanning helices
2 molecules of ACh are needed to bind
Found at NMJ, autonomic ganglia, CNS

Question 3

Number of subtypes exist vary in what?

Answer 3

In terms of their subunit composition

Question 4

nAChR located presynaptically don’t just reside on chollinergic nerves in CNS why?

Answer 4

Allows for cross-talk
Can also reside on neurones that use glutamate

Question 5

Patch clamping allows?

Answer 5

The study of single ion channels

Question 6

Why is a small glass pipette used in patch clamping?

Answer 6

To try and isolate single/smallpopulations of ion channels sitting on a cell

Question 7

Why does pipette have solution of physiological saline in it?

Answer 7

Acts as an electrode/has electrodes attached to it

Question 8

What does patch clamping record?

Answer 8

Record any differences between inside of the pipette and an earth point, by use of an operating amplifier
-Changes in current that occur as a result of a channel opening

Question 9

What is an NMDA receptor?

Answer 9

An ion channel receptor that respond to the excitatory amino acid glutamate

Question 10

Glutamate mediates its effects through? What receptors?

Answer 10

LGICRs and GPCRs

Question 11

Myasthenia graves is what condition?

Answer 11

Autoimmune condition resulting in reduction in nAChRs

Question 12

Depolarising block agents can be used for?

Answer 12

Cause muscular relaxation during surgeries

Question 13

NMDA receptor is an important receptor for?

Answer 13

Excitatory amino acid glutamate

Question 14

Tetrameric heteromers made up of subunits of how many?

Answer 14

7 different types

Question 15

Glycine is a co-agonist. What does this mean?

Answer 15

Receptor that has has another substance. To get full activation, glycine has to de also present
NMDA receptor

Question 16

Drugs that activate NMDA receptor.

Answer 16

Ketamine, memantine

Question 17

Ketamine is what type of receptor?

Answer 17

NMDA receptor antagonist

Question 18

Role of ketamine

Answer 18

Block depressive symptoms
- excess cortisol, neurotransmitters, can result in neural apoptosis leading to depressive symptoms

Question 19

Mematine effective in?

Answer 19

Glutamatergic transmission through interaction with NMDA receptors
Treatment of Alzheimer’s

Question 20

GABA A receptor important receptor for?

Answer 20

Inhibitory amino acid GABA

Question 21

GABA A receptor structure

Answer 21

Pentameric heteromers made up of 19 different types

Question 22

GABA bin ds to its recognition site, however when ion channel opens, it is permeable to?

Answer 22

Chloride ions

Question 23

If you make inside of a cell more negative what effect will this have? Link to GABA

Answer 23

Hyperpolarise and inhibit it

Question 24

Benzodiazepines is what to GABA? In terms of binding

Answer 24

Allosteric modulator, binds to its own recognition site

Question 25

How does benzodiazepines increase GABA interaction?

Answer 25

Potentates GABA as its own recognition site increasing likelihood of GABA interacting, greater effect of GABA, more hyperpolarisation
= increase cl-ion influx

Question 26

By having something that mimics action of GABA you can treat?

Answer 26

Epilepsy

Question 27

Benzodiazepines used for treatment of?

Answer 27

Anxiety, sedative epilepsy

Question 28

nAChR is what type of receptor?

Answer 28

Pentameric receptor ( made up of 5 subunits) with 2 binding sites for acetylcholine

Question 29

Types of ligand gated ion channels

Answer 29

Pentameric, tetrameric, trimeric, tetrameric

Question 30

Glutamate receptor is what type of receptor?

Answer 30

Tetrameric ligand gated ion channel
( ionotropic glutamate type)

Question 31

NMDA receptor is what type of ligand gated ion channel?

Answer 31

Tetrameric, calcium release type