Nicotine receptors.

I quit smoking (over 40 yrs.) a couple of months ago, and in the class the instructor said that nicotine is the only substance that makes it’s own receptors in the brain. At least I think that’s what she said.
Anyway, being a little dubious, I looked around for some more info, and found this
nicotine among some others. Nothing that I can tell that directly backs up what she said, though.
So I come to the SDMB. Is it true?
BTW; 2 1/2 months, and still jonesin’ a little. Not so bad, though.

“Chronic administration of nicotine increases the density of neuronal cholinergic nicotinic receptors in cells and in rodent brain, and similar increases have been reported in brains from human smokers…[the number of nicotine receptors] was significantly higher (250-300%) in…cortical regions from brains of smokers.”
Pubmed Abstract

I tried to read that abstract before I posted, FranticMad but got lost twice. :slight_smile: It does appear to support her claim. The part about this being unique for nicotine seems to be backed up by this, from the cite in my post;

By the way, nicotine also seems to protect against amyloid plaque buildup in brain cells. (It’s one of the things my lab is working on.)


What a choice, lung cancer or Alzheimers disease. Your research sounds interesting, Dogface

Nicotinic receptors are a type of acetylcholine receptor, so called because nicotine can activate the receptor. They are not there just for nicotine.

Drugs of dependence often lead to tolerance of the drug by the body and brain. The mechanisms are not that well understood, but generally the brain tries to adapt to the presence of the drug to maintain a status quo (homeostasis). Tolerance can be through increased metabolism of the drug but mainly through neuroadaptive changes in the brain. This means the amount of neorotransmitter and the way it is taken up is modified to adapt to the presence of the drug.

But, the brain is also always rewiring itself in response to the environment, according to Dr Susan Greenfield et al. I have seen a doco on the rewiring of the brain neurons themselves, in order to achieve a homeostatic adaptive change. This was for alcohol, which is thought to increases the number calcium channels in a receptor as a neuroadaptive change.

So, I think your teacher was a bit off the mark with ‘nicotine being the only substance to make its own receptors’, but nicotinic receptors can definately adapt to the drug and may even form more receptors in response.

Check out some of Dr Greenfields work - that may provide more clues.