Neuromuscular Junction

Question 1

What are the two different types of cholinoceptors on post-NMJ cells?

Answer 1

1. Nicotinic cholinoceptors
2. Muscarinic cholinoceptors

Question 2

How are acetylcholine neurotransmitters synthesised?

Answer 2

Question 3

What are the differences between end plate potentials and miniature end plate potentials?

Answer 3

Neurotransmitters are released in quanta and this can happen even in absence of action potentials – these cause local depolarisation of the end plate of the skeletal muscle fibre

These spontaneous releases of neurotransmitters causes small amplitude depolarisations in the end plate called miniature end plate potentials (MEPPs)

When an action potential in the pre-synaptic cell triggers neurotransmitter release, it causes a larger amplitude depolarisation in the end plate called end plate potentials (EPPs)

Question 4

What are the two ways in which neurotransmitters (ACh) are removed from the synaptic cleft?

Answer 4

Diffusion
Degradation

Question 5

How patch-clamp recording is used in this context?

Question 6

What is quantal content and how is it calculated?

Answer 6

Quantal content is the number of vesicles released per stimuli and can be calculated as follows:

Quantal content = mean EPP amplitude (mV)/mean MEPP amplitude (mV)