Nicotine and acetylcholine?

[seasurfer]

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Does nicotine molecular structure look alike acetylcholine? Why nicotine can replace acetylcholine to bind to nicotinic acetylcholine receptors? I saw their molecular structures, nicotine have 2 rings whereas acetylcholine got no ring at all. Why people are saying that nicotine and acetylcholine have almost the same structure and that is the reason why nicotine can bind to ACH receptors. Please help me, thanks a lot.

 

[FoxyDoc]

Nicotine can bind to nicotinic acetylcholine receptors. There are also muscarinic acetylcholine receptors which bind muscarine and other agonists. Hope this helps

 

[fava]

i am pretty sure that nicotine is a non-competetive antagonist of the ACh receptor. if that's the case (someone back me up on this?), then the structural dissimilarity between the 2 molecules would make sense.

 

[seasurfer]

Originally posted by fava
i am pretty sure that nicotine is a non-competetive antagonist of the ACh receptor. if that's the case (someone back me up on this?), then the structural dissimilarity between the 2 molecules would make sense.

Nicotine and acetylcholine look so different when I see their chemical structures. But I really don't understand why people has been saying that they act on ACh receptors because they look alike.

Why people has been saying that they look alike when it doesn't look alike....😕 😕 😕

 

[southerndoc]

Nicotine is actually an AGONIST to nicotinic receptors, including the acetylcholine receptors that are nicotinic.

 

[fava]

lol. good call. i suck.

 

[fava]

but nicotine and ACh do, at least, bind different sites on the nAChR, right??
(attempts redemption)

 

[nuclearrabbit77]

each receptor complex has two ACh-binding sites, about 30 A from membrane. each ach binding site is made up mostly from the alpha subunits.


i found this info about specific domains of nicotine on the receptor.

from journal:

Localization of agonist and competitive antagonist binding sites on nicotinic acetylcholine receptors.

Arias HR.


"Although some competitive antagonists such as lophotoxin and alpha-bungarotoxin bind to the same high- and low-affinity sites as ACh, other cholinergic drugs may bind with opposite specificity. For instance, the location of the high- and the low-affinity binding site for curare-related drugs as well as for agonists such as the alkaloid nicotine and the potent analgesic epibatidine (only when the AChR is in the desensitized state) is determined by the alphagamma and the alphadelta subunit interface, respectively. "

yes, i'm bored.


nuke

 

[benzo]

nicotine and other compounds such as lobeline are agonists of the nicotinic class of acetylcholine receptorsand as such bind to the Acetylcholine binding site. It is not necessary for the entire molecule to look similar to ACh for this to happen.

 

[benzo]

nicotinic agonists tend to have a trimethyl amine moiety that has been proposed as the functional group that interacts with the activation site. Both nicotine and acetylcholine posess similar amine structures. In acetylcholine the quaternary amine has three methyl groups attached and in nicotine one of the nitrogens is also attached to three methyl groups two of which are in the ring structure. In both cases the geometry of the arrangement is very similar. Now the rest of the molecule may indeed "look" different and may interact with different areas of the receptor, but just as long as that trimethyl nitrrogen is positioned where it needs to be the agent will act as an agonist.

 

[Adcadet]

Seasurfer -
my lab does nicotine research. My PI says that in fact nicotine and ACh do indeed resemble eachother, but can't easily visualize how. So if you can't, don't worry about it.

 

[seasurfer]

Thanks for telling me. I have been looking for an answer for this question everywhere, but to no avail.
🙂