Fig. 1.

Vaporized nicotine inhalation significantly increases blood cotinine levels in male and female mice. (a) Schematic diagram illustrates the vapor exposure system. Diagram denotes the following components of the apparatus: A, computer; B, panel vapor and voltage control; C, controller; D, syringe pump for liquid food delivery; E, cartridge; F, air flow regulator; G, plexiglass sealed box; H, left lever; I, left cue light; J, right lever; K, right cue light; L, food dispenser; M, air in; N, air out; O, vacuum pump. (b-c) Exposure to nicotine vapor (7.5 mg/mL) across a 1-hr session induced a substantial increase in blood cotinine, the main metabolite of nicotine, in both male (b) and female (c) mice. Blood samples were collected 2 h after the first vapor puff administration. Individual data points are represented on each graph, and graph bars express as the mean ± SEM ***p < 0.001.