抄録
KOYAMA, S., OHTSUKA, A. and HORIE, T. Eucapnic Hyperventilation-Induced Bronchoconstriction in Rabbits. Tohoku J. Exp. Med., 1992, 168 (4), 611-619- We examined whether eucapnic hyperventilation with dry air produces the bronchoconstriction in anesthetized, non-sensitized rabbits and in ovalbumin sensitized rabbits. Eucapnic hyperventilation challenge with dry air containing 5% CO2 at room temperature was performed with 4 non-sensitized and 7 sensitized rabbits by mechanical ventilation for 15min (120 breaths/min, 7ml tidal volume/kg body weight). Total lung resistance (RL) and dynamic compliance (Cdyn) were measured before and 0, 5, 15, and 30min after hyperventilation. In non-sensitized rabbits, RL and Cdyn did not change significantly. However, in sensitized rabbits, RL increased maximally by 48.9%±9.0% at 5min, and then decreased to the baseline level at 30min after challenge. Cdyn decreased maximally by 12.5%± 3.5% at 15min after challenge. These changes were significantly different from the baselines (p<0.05). Furthermore, to investigate the role of histamine on hyperventilation-induced bronchoconstriction (HIB) in sensitized rabbits, we performed the hyperventilation challenges in 5 sensitized rabbits with the pretreatment of H1-receptor antagonist (chlorpheniramine, 1mg/kg, i.v.) and found that the maximum increment of RL was suppressed to 24.2%±7.4% of the control, which was significantly lower than the maximal RL in nontreated sensitized rabbits (p<0.05). We concluded that HIB occurrs only in sensitized rabbits and that histamine may play an important role in the development of HIB in sensitized rabbits.-hyperventilation-induced bronchoconstriction; ovalbumin sensitized rabbits; chlorpheniramine
