Effects of neonatal immunization and repeated allergen exposure on airway responsiveness in the rabbit

Neonatal immunization of rabbits has previously been shown to enhance airway responsiveness to inhaled histamine. We investigated the influence of this immunization protocol on pulmonary parameters after inhalation of histamine in littermate allergen-immunized, sham-immunized, and saline-injected rabbits. In spontaneously breathing rabbits, inhalation of histamine caused a concentration-dependent increase in total lung resistance (RL) and respiratory rate (RR) and a reduction in dynamic compliance (Cdyn). Allergen-immunized rabbits were significantly more responsive to histamine than their control littermates and saline-injected animals when the concentration-effect curves were analyzed in terms of changes in RL (P 0.05). The effect of inhaled AMP on pulmonary function in allergen-immunized and native animals was also ...