Table 1

 Possible effects of increases in amount of free-base nicotine delivered

Increased oral absorptionIncreased activation of oral sensory receptorsHeightened sensory “cue” for nicotine delivery
Increased efficiency of respiratory depositionGreater retention of total smoke nicotineGreater availability of nicotine for deposition/absorption
Increased volatility from inhaled particlesMore rapid absorption of nicotine in lung tissueReduced time course of delivery to brain