CNS channelopathies 2 Flashcards Preview

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Flashcards in CNS channelopathies 2 Deck (15)
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1

What is the fundamental causes of epilepsy

Too much activity in excitatory neurons due to changes in ion channels - fire too many APs
Too little activity of inhibitory neurons which aren't working well - no dampening of excitation

2

What is the role of Nav channels

Depolarization in both excitatory and inhibitory neurons

3

What is the role of K channels

Repolarization in both excitatory and inhibitory neurons

4

What is the role of Ca in neuronal ion channels

Evokes the release of neurotransmitters

5

What is the role of AchR in neuronal ion channels

Post synaptic membrane excitation

6

What is the role of GABAa receptors in neuronal ion channels

Post synaptic membrane inhibition

7

What is the role of HCN in neuronal ion channels

Hyperpolarization - activated cyclic nucleotide gated channel - open probability goes up as the membrane potential hyperpolarizes - leading to depolarization - important in determining how many APs are fired per unit time

8

How does a P/Q type Ca channel mutation cause epilepsy

No neurotransmitter release at the inhibitory presynapse
No GABA release so no Cl influx - no hyperpolarization of excitatory neuron so they become over excitatory

9

How does a Nav1.1 channel mutation cause epilepsy

Nav1.1 found in the inhibitory neuron - mediates depolarization of the axon to fire AP - intracellular calcium remains low - less GABA release - less inhibition

10

What mutations are seen in the Nav1.1 channel

either missense or truncation - scattered throughout the protein

11

What is the mutation seen in AchR and where are they found

Gain of function mutation - found on the post synaptic membrane of the excitatory neurons

12

What is the mutation in the Nav1.2 channel and where are the channels found

Gain of function - found on the excitatory axons

13

What is the mutation in the HCN channel and where are the channels found

Loss of function mutation - Found on the excitatory dendrites - Increases excitability due to loss of firing control

14

What is the mutation in the Kv7.2 channel and where are the channels found

Loss of function - found on the excitatory axon - Increase in excitability due to loss of firing control

15

How does Nav1.7 channel mutations lead to pain disorders

Found in peripheral sensory neurons
Mutations cause lack/gain of pain depending on if it is a loss or gain of function mutation