The primary aim of this project is to determine the threshold dose of nicotine, which the
smokers will be able to differentiate from placebo (saline). Will use IV pulsed-nicotine
infusion that closely matches nicotine delivery by inhaled tobacco use (i.e., tobacco
cigarette or electronic cigarette), allowing precise and reproducible nicotine delivery. Four
nicotine doses (0.1, 0.05, 0.025, and 0.0125 mg nicotine/pulse) which are within the range of
nicotine doses that are delivered by cigarettes with very low to regular nicotine content.
These doses will be delivered as a cluster of 4 pulsed-nicotine infusions of 2 sec duration
with a 28 sec interval between each dose.