Nicotine enters the bloodstream through the lungs (when inhaled), mouth, or skin, depending on the mode of consumption. It binds to nicotinic acetylcholine receptors in the brain, leading to the release of neurotransmitters like dopamine, which creates feelings of pleasure and reward. However, prolonged exposure can result in dependence, and quitting can lead to withdrawal symptoms such as irritability, anxiety, and cravings.
