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Why can nicotine increase alertness and heart rate?
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Nicotine increases alertness and heart rate by acting on the nervous system through its interaction with specific receptor proteins known as nicotinic acetylcholine receptors (nAChRs).12
When nicotine binds to these receptors in the brain and peripheral nervous system, it triggers the transmission of nerve impulses to various target organs and tissues. This process stimulates the release of several neurotransmitters, including dopamine, norepinephrine, and acetylcholine.231
Specifically, nicotine prompts the adrenal glands to release epinephrine and norepinephrine. These chemical messengers are responsible for the physiological changes that heighten alertness and concentration, as well as the increase in heart rate and blood pressure.2