Sensory adaptation, how exactly does this occur?

[scilearner]

Hello everyone,

 

I read many articles on this, but they all just say what it is and does not mentions how it occurs. This is a quote from another user not from here.

 

Experimentally you can demonstrate adaptation. If you trigger an action potential by eg a 20 mv depolarisation of membrane potential. Now if you do say 2 or 3 smaller pre depolarizations and then do 20 mv depolarisation as you initially did then you no longer see an action potential. The reason is that chronic depolarisation even if quite small causes the sodium channel to go into a locked closed configuration - so no further action potentials are possible. There are also mechanisms by which the receptor system itself can accommodate, those will be specific to the specific receptor system involved

 

1. So if sodium channels go into locked position, does this increase the threshold for the stimulus. Let's say if previous threshold was -20, and then sodium channes got locked in, but threshold should stay the same right, it is just that there is a barrier to reach the previous threshold.

2. How do sodium channels get locked up, and does this decrease the frequency of action potential or inhibit?

3. How do we adapt to smell?

4. For receptor changes I'm assuming, that displacemnet of lamella in pacinian corpuscle reducing pressure as an example.

 

Thanks

[SMF]

Working voltage gated sodium channels are necessary for an action potential to occur because it is part of the mechanism.