Table 3.

Change in mucosal MPO activity after nicotine intake and nitric oxide donor (NO) treatment

	Tap water + no stress	Tap water + stress	Nicotine + stress	Nicotine + stress + NO (acute)	Quit nicotine + stress	Quit nicotine +stress + NO (chronic)
MPO (u/g protein):	6.3 ± 0.7	9.3 ± 1.1a	9.1 ± 1.0a	7.9 ± 0.9	9.4 ± 1.2a	5.7 ± 0.9b

Values are mean ± SD. Each group had 8 rats. Stress: restrained at 4 °C for 2 hours. Tap water: Rats drank water (control). Nicotine: Rats drank nicotine 50 μg/ml for 20 days. Quit nicotine: Rats drank nicotine (50 µg/ml) for 20 days, then, nicotine was replaced by water for another 10 days. NO (acute): Rats drank nicotine (50 µg/ml) for 20 days, the rats were then given NO donor 60 and 10 min by oral gavages before stress. NO (chronic): Rats drank nicotine (50 µg/ml) for 20 days, then, nicotine was replaced by water, the rats were given NO donor three times daily by oral gavages for 10 days before experiment.

^aP < 0.05 vs its own corresponding group in tap water + no stress control.

^bP < 0.05 vs its own corresponding group in tap water + stress control.