How does nicotine affect the brain and nervous system?

Nicotine, a naturally occurring alkaloid found in tobacco plants, acts on the nervous system by binding to nicotinic acetylcholine receptors located in the brain and peripheral nerves.123

When nicotine binds to these receptors, it functions like a key in a lock, triggering neurons to transmit nerve impulses and release various neurotransmitters, including dopamine, norepinephrine, acetylcholine, and serotonin. This process results in several physiological and psychological effects:123

• Stimulation: Nicotine acts as a stimulant, increasing alertness, concentration, and heart rate.123
• Reward and Addiction: The release of dopamine within the brain’s reward pathways reinforces nicotine use, creating pleasurable effects that drive addiction.134
• Tolerance and Dependence: With continued use, the brain alters the number and sensitivity of its receptors, leading to tolerance. This requires users to consume larger or more frequent doses to achieve the same effects, eventually resulting in physical dependence and withdrawal symptoms when use is stopped.234