Inhaled cigarette smoke stimulated vagal bronchopulmonary C-fibers via an action of nicotine on neuronal nicotinic acetylcholine receptor (nAChR). Recent studies have reported that nicotine at high concentrations can also activate the transient receptor potential ankyrin 1 receptor (TRPA1) expressed in these sensory nerves. This study was carried out to characterize the airway response to inhaled nicotine aerosol and to investigate the relative roles of nAChR and TRPA1 in this response. Guinea pigs were anesthetized and mechanically ventilated; one tidal volume of nicotine aerosol (2% solution) was diluted by equal volume of air and delivered directly into the lung via a tracheal cannula in a single breath. Our results showed: 1) Inhalation of nicotine aerosol triggered an immediate and pronounced bronchoconstriction; the increase in total pulmonary resistance (RL) reached a peak of 588 {plus minus} 205% in 10-40 sec, which gradually returned to baseline after 1-5 min. 2) Pretreatment with either atropine (i.v.) or mecamylamine (aerosol) almost completely abolished the nicotine-induced bronchoconstriction; the mecamylamine pretreatment did not block the bronchoconstriction and bradycardia evoked by electrical stimulation of the distal end of one sectioned vagus nerve, indicating its minimal systemic effects. 3) Pretreatment with HC-030031, a selective TRPA1 antagonist, abolished the bronchoconstriction induced by allyl isothiocyanate, a selective TRPA1 agonist, but did not attenuate the nicotine-evoked bronchoconstriction. In conclusion, inhalation of a single breath of nicotine aerosol evoked acute bronchoconstriction mediated through the cholinergic reflex pathway. This reflex response was triggered by activation of nAChR, but not TRPA1, located in airway sensory nerves.