Voltage Gated Sodium Channels

[richierich]

I was wondering if anyone could help me understand how exactly the tetrodotoxin interacts with the sodium channels. I understand that they bond to a peptide chain and replace the sodium for a couple seconds. I tried to understand what wikipedia was telling me but it was way to wordy and hard to understand. I used this site and it was a lot more helpful, but i was wondering if someone could put it in laymans terms.

http://courses.washington.edu/conj/membrane/nachan.htm

thanks, Rich

 

[Abrahm]

Very simply what tetrodotoxin does is bind to a specific site on a peptide that caused the toxin molecule to block the channel (making it sterically* impossible for the ions to enter or possibly causing a conformational** change) that is used to pump sodium.

*Because of size or electric charge
**A change to the channel like tetrodotoxin binding can often cause the protein to take a different shape which may cause the protein to not work as it is supposed to.

 

[richierich]

thanks Abrahm. That is what I gleaned from the website, but i was unsure if my assumptions were correct.

 

[Abrahm]

It's pretty interesting stuff. I'm glad you brought it up so I could take a look at it. Very interesting that tetrodotoxin does not effect cardiac muscle but instead causes death by paralyzing the diaphragm. I love biochemistry and I really wish I could take more classes in it. Pharmacology and toxicology would be especially fun ones.

 

[richierich]

I love Biochem too. I had no reason to even look up the molecule of TTX but I just did because I wanted to. I also wonder why the cardiac tissue is not paralyzed and the diapragm is. When I go to university next year, I would like to find room in my schedule for some kind of toxicology class. Are you going to university for chemistry or a different branch of biochem? Does this mean that Taricha has developed an immunity to its own toxin by altering its sodium channels like the pufferfish?