Nicotine Receptors & Bupropion: How an Antidepressant Blocks Smoking

Most people think nicotinic receptors exist for nicotine — but they actually evolved for acetylcholine, a completely different molecule. This episode unpacks the bizarre naming accident, the structure of these pentameric ion channels, and how they function as gain controllers throughout the brain. Then we dive into bupropion: an antidepressant that was serendipitously discovered to help people quit smoking. It turns out bupropion is a non-competitive antagonist at key nicotinic receptor subtypes, blocking nicotine's effects while also reducing withdrawal. We explain the dual mechanism, the clinical protocol, and why this approach differs from nicotine replacement therapy.