5.3 Neuronal Communication - Synapses; Neurotransmission

Question 1

What is the name given to the neuron that exists before and after a synapse?

Answer 1

Presynaptic/Postsynaptic cell

Question 2

What are the three structures that neurons tend to connect with?

Answer 2

• Neurons
• Muscles
• Glands

Question 3

What is the name of the space between two neurons?

Answer 3

Synaptic cleft (the whole joining area is the synapse)

Question 4

Which type of junctions are used in electrical synapses?

Answer 4

Gap junctions

Question 5

Why don’t we have huge neurons with fewer synapses?

Answer 5

Different neurotransmitters can be used for different things; more synapses means more versatility

Question 6

Give an example of an excitatory and inhibitory neurotransmitter

Answer 6

Excitatory: Glutamate
Inhibitory: GABA

Question 7

Would it make sense for channels on post-synaptic neurons to be ligand-gated or voltage-gated?

Answer 7

Ligand gated

Question 8

In terms of charge, explain the action of inhibitory neurotransmitters

Answer 8

• Allow influx of negative ions
• Takes the overall charge further from threshold, decreasing AP likelihood

Question 9

Does one neurotransmitter always have only one effect?

Answer 9

• No
• They can have different effects at different sites

Question 10

What are three fates of neurotransmitters?

Answer 10

1. Broken down by enzymes
2. Reabsorbed by the pre-synaptic neuron
3. Recycled by astrocytes

Question 11

Which types of receptors does metabotropic neurotransmission depend on?

Answer 11

G-Protein coupled receptors

Question 12

Describe metabotropic neurotransmission

Answer 12

• Ligand binds to receptor
• This activates other effector proteins

Question 13

What are the four main types of neurotransmitters?

Answer 13

Faster:
- Amino Acidergic
Slower:
- Catecholaminergic
- Serotonergic
- Cholinergic

Question 14

Which receptors does glutamate bind to

Answer 14

NMDA or AMPA receptors

Question 15

Is glutamate ionotropic or metabotropic?

Answer 15

Both

Question 16

What happens if too much glutamate is present?

Answer 16

Excitotoxicity

Question 17

Which receptors does GABA bind to?

Answer 17

GABA receptors

Question 18

Is glutamate ionotropic or metabotropic?

Answer 18

Both, also

Question 19

What happens with too much/little GABA?

Answer 19

Too Much: Coma
Too Little: Seizure

Question 20

What is the precursor for classical amine neurotransmitters?

Answer 20

Tyrosine

Question 21

What is the rate limiting enzyme that effects production of classical amine neurotransmitters?

Answer 21

Tyrosine hydroxylase

Question 22

What are the two main families of acetylcholine receptor? What type of receptors are they?

Answer 22

• Nicotinic (ionotropic)
• Muscarinic (metabotropic)

Question 23

Where are nicotinic receptors synthesised?

Answer 23

All motor neurons

Question 24

What effects do nicotinic receptors have?

Answer 24

Skeletal muscle contraction

Question 25

What are the effects of muscarinic receptors?

Answer 25

Sweat glands: excitatory
Cardiac muscle: inhibitory

Question 26

Why care about neurotransmitters & the receptors they bind to?

Answer 26

[Review Slides]

Question 27

What is an EPSP?

Answer 27

• Excitatory post-synaptic potential
• Makes postsynaptic neuron more likely to generate an AP

Question 28

What is an IPSP?

Answer 28

• Inhibitory post-synaptic potential
• Makes postsynaptic neuron less likely to generate an AP

Question 29

What is spatial summation?

Answer 29

When there are multiple EPSPs close together to produce a larger net effect

Question 30

What is temporal summation?

Answer 30

When post-synaptic membrane is depolarized in rapid succession