Ligand Gated ion channel receptors

Question 1

what is required to activate ligand gated ion channel receptor (LGICR)

Answer 1

2 agonist molecules

Question 2

nicotinic cholinoceptor - agonist (stimulated by)

Answer 2

ACh

Question 3

5HT3 - agonist?

Answer 3

5-HT

Question 4

GABAa agonist?

Answer 4

y amino butyric acid (GABA)

Question 5

Glycine agonist?

Answer 5

glycine

Question 6

nicotinic vs muscarine define

Answer 6

nicotinic receptor- group of cholinergic receptors linked to ion channels in the cell membrane ; made of 5 similar proteins to create an ion pathway
muscarinic receptor- group of G-protein coupled cholinergic receptors that phosphorylate second messenger - made up of 1 protein that talks to G proteins

Question 7

adrenergic vs cholinergic

Answer 7

adrenergic-work on sympathetic nervous system
cholinergic- work on the parasympathetic nervous system

Question 8

Stimulation of nicotinic AChR in skeletal muscle

Answer 8

contract muscle quickly

Question 9

Stimulation of nicotinic AChR in post-ganglionic nerve

Answer 9

depolarises quickly

Question 10

Nicotinic type acetylcholine receptors: structure in skeletal muscle ADULT

Answer 10

Two a1, epsilon , b1, delta (adult)

Question 11

muscle nicotinic acetylcholine receptor from its subunit composition: foetal

Answer 11

Two a1, gamma, b1, delta (foetal)

Question 12

Nicotinic type acetylcholine receptors: structure in CNS

Answer 12

a2 to a8
b2 to b4

Question 13

Nicotinic and 5HT3 ligand gated ion channel: depolarises/hyperpolarises?

Answer 13

depolarises due to Na/Ca influx

Question 14

GABAA and Glycine ligand gated ion channel: depolarises/hyperpolarises?

Answer 14

Hyperpolarises (chloride efflux)

Question 15

myasthenia gravis?

Answer 15

autoimmune disease
when muscle nicotinic AChRs become degraded
targets a1 subunit: therefore neuronal nicotinic AChRs unaffected: a2-a8 & b2-b4

Question 16

symptoms of myasthenia gravis

Answer 16

Muscle weakness
Drooping eyelids
Fatigue
Difficulty swallowing/talking
Exertion is difficult

Question 17

Acetylcholine causes skeletal muscle to contract (shorten) very quickly. It does this by stimulating a receptor made of 5 proteins. How does this receptor structure cause a cell response so fast?

Answer 17

The 5 proteins associate to create an ion path
Each protein subunit has 4 transmembrane domains and the second one contributes 1/5th of the amino acids to form an ion flux pathway when the receptor is activated.

Question 18

The nicotinic acetylcholine receptor (nAChR) is an example of a ligand gated ion channel which of the following statements is correct about this receptor?

Answer 18

It is comprised of 5 similar proteins
Two molecules of acetylcholine bind to produce full receptor activation
Over 10 different forms of the nACHR protein exit

Question 19

Myaestheisia gravis is an autoimmune disease of nicotinic acetylcholine receptors. With this disease skeletal muscle transmission is affected but not ganglionic transmission. Why is this?

Answer 19

It is an autoimmune disease and the immunogenic peptide is the alpha1 subunit only found in muscle nicotinic acetylcholine receptors. Ganglion has alpha2 to alpha8