levels. A cigarette delivers 1.2-2.9 mg of nicotine, and the typical one pack-per-day smoker absorbs 20-40 mg of nicotine each day, raising the plasma concentrations to between 23-35 ng/mL. Nicotine produces increased expression of brain nicotine receptors, changes in regional brain glucose metabolism, the release of catecholamines, tolerance, and physiologic dependence. Nicotine addiction results from positive reinforcement (with the administration of nicotine) and withdrawal symptoms that start within…
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