TTX Flashcards
What does TTX stand for?
Tetrodotoxin.
How does TTX work?
It is a specific blocker of the pore of sodium channels.
How do a- and B-scorpion toxins work, respectively?
a-scorpion toxin = blocks fast inactivation.
B-scorpion toxin = enhances activation.
Both generate persistent sodium current that causes depolarisation block of nerve conduction.
Where is TTX most concentrated?
In the liver and ovaries of pufferfish.
List the symptoms of mild TTX poisoning.
Pleasant tingling sensation and slight numbness in lips and extremities.
List the symptoms of severe TTX poisoning.
Nausea.
Sweating.
Pupil dilation.
Ataxia.
Paralysis.
Respiratory failure.
Death.
What does DDT stand for?
Dichlorodiphenyltrichloroethane.
How does DDT work?
Opens Nav channels to cause uncontrolled firing.
Why is TTX useful in the lab?
It can be used to block action potentials and therefore dissociate activity in cells and circuits which depends on the intrinsic activity of synapses and cells.
What does using TTX in the lab allow us to look at?
Signal processing mechanisms of dendrites.
Constant turnover of NT release at chemical synapses.
Mechanisms that cells use to make sure their plasticity mechanisms don’t change synaptic weights too much.
What is lidocaine used for?
Common local anaesthetic agent.
How does lidocaine work?
Blocks Nav to prolong the activation of the channel and keep them like they are during the refractory state.
What is flecainide used for?
Treats episodes of superventricular tachycardias.
How does flecainide work?
Blocks Nav1.5.
