hyperpolarization vs depolarization

[reburbia]

Advertisement - Members don't see this ad

when a stimulus depolarizes a postsynaptic neurons, acetycholine binds to chemically-gated Ca+2 ion channels on the postsynaptic neuron.

Ive also heard that a stimulus can hyperpolarize (inhibit) the postsynaptic neuron. How does this mechanism work?

 

[chiddler]

acetylcholine binds receptor mediated sodium channels not calcium. their activation allows sodium inside which depolarizes the post synaptic neuron.

the mechanism for hyperpolarization is usually allowing Cl- to enter the cell or to block potassium leak channels.

 

[reburbia]

Sorry, Na+ not Ca+2 channels.

So how are those Cl- or K+ channels activated or blocked respectively? Does it always involve a neurotransmitter or can the electrical stimulus itself do it, as in the case of voltage-gated Na channels?

 

[chiddler]

As far as I know, as a humble premed, it is always in the case of neurotransmitter for Cl(-), and an inhibitor for K+. I don't think neurotransmitters would block potassium leak channels.

For mcat purposes you really don't have to know that much more detail.

 

[Morsetlis]

For mcat purposes you really don't have to know that much more detail.

Correct.

And nobody really likes thinking about ion channels anyway 😛