Effects of isoprenaline on the responses of slowly adapting pulmonary stretch receptors to reduced lung compliance and to administered histamine.

To define the difference between the responses of slowly adapting pulmonary stretch receptors (SARs) to reduced dynamic lung compliance (Cdyn) and to administered histamine, experiments were performed in open-chest, artificially ventilated, bilaterally vagotomized rabbits with positive end-expiratory pressure (PEEP). Both stimuli caused an increase in tracheal pressure and produced augmentation of SAR activities during inflation and deflation. Isoprenaline treatment that blocked the responses of SARs and PT to histamine had no effect on those to reduced Cdyn. The results suggest that the response characteristics of SARs provoked by histamine administration do not involve the contribution of decreased Cdyn.