Figure 1.

Saliva cotinine in rhesus monkeys receiving 8.9 mg·kg⁻¹·day⁻¹ of nicotine. Abscissae: hour of day, spanning the first to the last dose of nicotine, on the first day of daily nicotine administration (top) and consecutive days of nicotine treatment (bottom). Ordinates: mean ± SEM (n = 5) cotinine in ng·mL⁻¹ of saliva. Nicotine was administered at a dose of 1.78 mg·kg⁻¹ every 2 h beginning at 08 h and ending at 18 h. The arrows show time of nicotine administration. Open circles are cotinine levels immediately before the first daily dose (8 AM), and closed circles are cotinine levels immediately before the last daily dose (6 PM).