If Nicotine Prefered Muscles Over Brains a Cigarette Would Kill.

Nicotine (center) nestled into brain receptor "box."

Scientists figured out why the nicotine molecule likes brain receptors over muscle receptors. This finding may shed light on the addictiveness of smoking and also some new ways for people to stop smoking. For nicotine to interact with its receptor it must bind and having opposite charges on the molecule and the receptors binding site(box) helps it to bind. The nicotine receptors in the brain and in the muscles are almost identical, nicotine has a positive charge and both the brain and muscles have a negative charge. So why does the brain like nicotine and not muscles?

Dennis Dougherty a chemist at the California Institute of Technology, after a decade of work his colleagues have found that one single amino acid makes the difference between where the nicotine binds. The brain receptor has a lysine molecule but the muscle has a glycine molecule. Nicotine binds there because the lysine changes the shape of the brains receptor box and its negative charge makes it more available to nicotine.

In the muscles the molecule acetylcholine which helps muscles contract, when the muscle receptor glycine is switched out for lysine it accepted the nicotine like it was acetlycholine. Smoking would immediately trigger abnormal contrctions that would paralize muscles, like those involved with breathing. Scientists can olly speculate why the brain and muscle receptors differ so much. The studying of the binding interactions and the nicotine receptors might lead to new ways of helping people stop smoking, but also new treatments for illness such as Alzheimer's disease, autism, Parkinson's disease, and schizophrenia.


Samantha DeBiasio (week 5)