week 12 L1: Skeletal neuromuscular junction

Question 1

Is the skeletal NMJ fast or slow?

Answer 1

fast neural communication

Question 2

The 5 steps of synaptic transmission of NMJ?

Answer 2

synthesis, storage, release, activation, inactivation

Question 3

What 2 ways can drugs enhance synaptic transmission?

Answer 3

direct and indirect

Question 4

Direct stimulation of post synaptic receptors?

Answer 4

a) natural transmitter b) analogues of transmitter

Question 5

Indirect action via?

Answer 5

a) increased transmitter release

b) inhibition of transmitter removal (stay in synapse)

Question 6

How can drugs inhibit synaptic transmission? (2)

Answer 6

> blocking synthesis, storage or release from presynaptic neurone.
blocking post-synaptic receptors.

Question 7

Name the 2 important properties of agonists?

Answer 7

affinity and efficacy

Question 8

What is efficacy?

Answer 8

ability of agonist, once bound to a receptor, to initiate a biological response.

Question 9

What is affinity?

Answer 9

Ability to bind to receptor.

Question 10

Difference between agonist and antagonist?

Answer 10

antagonist has affinity but lack of efficacy

Question 11

What is a competitive receptor antagonist?

Answer 11

competes with agonist for “agonist binding site”

reversed by increased agonist concentration

depends of conc of agonist and antagonist

Question 12

What are the 2 regions of ACh?

Answer 12

acetyl moiety

choline moiety

Question 13

What are ACh neurones called?

Answer 13

Cholinergic

Question 14

What are the receptors called that ACh acts on?

Answer 14

Cholinoreceptors

Question 15

Name the 2 types of cholinoreceptors

Answer 15

Nictoninic and Muscarinic

Question 16

Nicotinic Cholinoreceptors?

Answer 16

> fast
activated by ACh and >nicotine
transmitter gated ion-channel family

Question 17

Muscarinic Cholinoreceptors?

Answer 17

> slower
activated by ACh or muscarine
g protein coupled receptor

Question 18

Nicotinic Cholinoreceptor subunits?

Answer 18

5 sub-units

2 alpha, beta, delta, gamma

Question 19

What moves through the pore of the nicotinic cholinoreceptor?

Answer 19

Na+ moves into cell

depolarisation of muscle cell at end-plate region ~-40mV

Question 20

What is an example of a nicotinic cholinoreceptor?

Answer 20

nicotinic acetylcholine Receptor (nAChR)

Question 21

What technique is used to record activity or a single receptor?

Answer 21

cell attached patch

Question 22

What is in the cell attached patch solution?

Answer 22

NaCl and ACh

Na+ to flux through receptor and current is taken.