What does a-tubocurarine do?
Blocks the nicotinic acetyl choline receptor, so it acetyl choline can't bind --> leads to paralysis.
Number of trans-membrane spanning domains that each of the nicotinic acetyl choline receptor SUB-UNITS has.
Three different function states of the nicotinic acetyl choline receptors?
1) Resting. Receptor gate is closed. 2) Activated. Receptor gate is open, lets K+ out and Na+ in. (NB this occurs after TWO ACh molecules have bound to the receptor). 3) Desensitised. Gate closes. The 2 ACh molecules are still bound, but the receptor becomes desensitised and closes. Eventually the two ACh molecules detach and the receptor goes back to resting state.
Inhibits the AChE enzyme, which usually would act to degrade acetyl choline. Used to treat myasthenia gravis (but this treatment only lasts for 20mins or so)......
Where is the muscarinic acetyl choline receptor found?
In the CNS, at axon terminals. Also in heart muscle.
What are the FOUR steps to the muscarinic acetyl choline receptor function?
1) ONE acetyl choline molecule binds to receptor (GPCR). 2) The g protein associated with the muscarinic ACh receptor has the GDP fall off its alpha subunit, 3) GTP binds to the alpha subunit. 4) The now activated G protein binds to the K+ channel, opens it, and now K+ can flow out..