Nicotine Binding

An accomplished mimic, nicotine competes with acetylcholine to bind to the acetylcholine receptor. It wins and, like the vanquished chemical, opens ion channels that let sodium ions into the cell (see light blue dots). But there's a lot more nicotine around than acetylcholine, so a much larger current spreads across the membrane. This bigger current causes increased electrical impulses to travel along certain neurons. With repeated smoking, the neurons adapt to this increased electrical activity, and the smoker becomes dependent upon the nicotine.

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