FIG. 1.

Tobacco smoke exposure elicits increases in cytosolic Ca²⁺ in HBECs. Changes in Fluo-8 levels were measured by epifluorescence as an indicator of cytosolic Ca²⁺ levels following acute exposure of 10 filtered puffs of air/smoke for Kentucky reference cigarettes, three brands of little cigars, and three brands of commercial cigarettes (n = 8/group). Data are shown as peak changes (F/F₀). (A) Time trace of fluorescence changes for air (open black circle), Kentucky (grey square), and Cheyenne (black triangle) cigarette exposure. Cells were exposed to air or smoke for 10 minutes, and fluorescence was measured for 17 minutes at 30-second intervals. (B) Fluorescence measured after 16 minutes of exposure for air, Kentucky, Swisher Sweets, Captain Black, Cheyenne, Marlboro, Newport, and Camel cigarettes. *p < 0.05. HBEC, human bronchial epithelial cell.