Acetylcholine

Question 1

what is the only common feature between nicotinic and muscarinic ACh receptors

Answer 1

the amino acid sequence of the ACh binding site

Question 2

what is the structure of muscarinic ACh receptors

Answer 2

single polypeptide, 7 transmembrane domains

Question 3

are muscarinic ACh receptors ion channels or G protein coupled receptors

Answer 3

G protein coupled receptors

Question 4

what are the precursors and enzyme used in ACh synthesis

Answer 4

choline, acetyl CoA, cholineacetyltransferase

Question 5

how is ACh taken up into vesicles

Answer 5

through a vesicular ACh transporter

Question 6

how is ACh removed from the synaptic cleft

Answer 6

1) diffuses away
2) broken down by acetylcholinesterase into acetate and choline

acetate feeds into Kreb’s cycle

choline taken up through choline transporter

Question 7

are nicotinic ACh receptors ligand gated cation channels or g protein couple receptors

Answer 7

ligand gated cation channels

Question 8

how many subunits are nAChR formed of

Answer 8

5

Question 9

what are the 2 most common combination of subunits of nAChR in the CNS

Answer 9

1) 2 alpha4, 3 beta2

2) 5 alpha7

Question 10

which has a higher sensitivity to ACh?

Answer 10

alpha4 (2), beta2 (3)

Question 11

which ions channel closes faster after ACh binding

Answer 11

Alpha7 homopentamer

Question 12

how many mols of calcium does each channel let in for every sodium ion

Answer 12

alpha7 homopentamer - 10

other - 1

Question 13

where is the a7 homopentamer found in the CNS

Answer 13

hippocampus, cortex

Question 14

where is the 2 alpha4, 3 beta2 channel found in the CNS

Answer 14

thalamus, cortex

Question 15

how many types of muscarinic receptors are there

Answer 15

5

Question 16

varenicline is a partial agonist to which type of nAChR. what is the drug used to treat

Answer 16

those containing a4 subunits. used to treat nicotine dependance

Question 17

name two AChesterase inhibitors

Answer 17

Galantamine, rivastigmine

Question 18

nicotine causes release of which neurotransmitter

Answer 18

Dopamine

Question 19

nicotine downregulates expression of nAChRs. true or false

Answer 19

false. it upregulates expression of nAChRs

Question 20

name two examples of muscarinic antagonists. what are they usually used to treat

Answer 20

benztropine, biperiden. early stages parkinson’s

Question 21

give an example of a nAChR channelopathy

Answer 21

autosomal dominant nocturnal frontal lobe epilepsy

Question 22

what gene is mutated in ADNFLE? what are the consequences on protein structure

Answer 22

gene coding for alpha4 subunit in nAChR 2 alpha4, 3 beta2. causes 2nd transmembrane domain (of 4) to change

Question 23

what are the consequences of a mutated 2nd transmembrane domain in an alpha subunit of a 2 alpha4, 3 beta2?

Answer 23

causes inhibition of Calcium channels on presynaptic terminals of GABA neurons.

ca entry inhibited - less release of GABA which is inhibitory

less inhibition - hyperexcitation