CNS channelopathies 1 Flashcards Preview

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Flashcards in CNS channelopathies 1 Deck (10)
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What is ataxia

Uncontrolled muscle contraction


What are triggers for both type 1 and type II episodic ataxias

Physical/ emotional stress - sudden changes in position


What are some common symptoms of both type I and type II ataxias

Ataxia, dizziness, vertigo, visual blurring


What is the cause of type I ataxia

Brief shaking attacks - KCNA1 gene mutation
Channel is found in the cerebellum and at neuromuscular junctions - Loss of function mutations scattered throughout subunits of the channel


How does a mutation in KCNA1 cause ataxia

K channel usually mediates repolarization so neurons become excited for longer inappropriately


What is a treatment for episodic type I ataxia

Acetazolamide - carbonic anhydrase inhibitor - changes body fluid pH dampening the excitability of neurons


What is the mutation that causes episodic type II ataxia

30min->24hr shaking attacks
P/Q type Calcium channel CaCNA1A mutation found in the cerebellum
Many point mutations and mostly truncation mutations


What is the structure of the P/Q type calcium channel

24 TMDs - 4 sets of 6 which each form a pore subunit


Where is CACNA1A found

In purkinje cells and granule cells of the cell bodies of central neurons - Calcium firing acts as a signal for neurotransmission by exocytosis
Less firing due to a reduction in calcium - less ability to co-ordinate movements - normal cerebellar function


What does the G293R mutation cause

calcium flow is reduced
Caused by a change in voltage dependence
Calcium gets max flow at +10mV instead of 0
Means they take longer to open and are open for a shorter amount of time
Less Ca means less neurotransmitter release
Problems with skeletal muscle control