We examined whether inhalation of hypertonic saline can induce bronchoconstriction in guinea pigs, and also studied the mechanisms of this bronchoconstriction. Twenty-five male Hartley guinea pigs were divided into the following 5 groups: G-1, 0.9% saline inhalation; G-2. non-treatment and inhalation of hypertonic saline; G-3, capsaicin pretreatment and inhalation of hypertonic salines; G-4, ipratropium bromide pretreatment and inhalation of hypertonic saline; G-5, chlorpheniramine pretreatment and inhalation of hypertonic saline. RL and Cdyn were serially measured to assess bronchoconstriction, and the percent increase in RL from the value measured before inhalation of hypertonic saline (%RL) was analyzed. The maximum %RL was 9.2 +/- 3.8% in G-1, 90.6 +/- 6.6% in G-2, 11.2 +/- 5.7% in G-3, 9.0 +/- 6.0% in G-4, and 47.8 +/- 4.0% in G-5. The values in G-3 and G-4 were significantly lower than in G-2. We conclude that inhalation of hypertonic saline causes concentration dependent bronchoconstriction in guinea pigs and that both non-adrenergic non-cholinergic nerves and cholinergic nerves may play an important role in this bronchoconstriction.