Comparative investigation of the effects of zardaverine and theophylline on pulmonary function in rats

Zardaverine is a new selective phosphodiesterase (PDE) III/IV inhibitor. The bronchodilating and bronchoprotective potency of zardaverine and the nonselective PDE inhibitor theophylline was compared by measuring typical spontaneous and forced respiratory function parameters in anesthetized female Wistar rats using whole-body plethysmography. Zardaverine and theophylline were given orally in 4% Methocel/0,9% saline solution 20 min before measurement. One week before treatment, control measurements were performed in the same animals after administration of the vehicle. When spontaneously breathing, the 30 um mol/kg zardaverine-treated animals showed significant changes: a 23% (14% ns) decrease in lung resistance and a 43% (25%) increase in dynamic compliance. These changes can be interpreted as an indication of bronchodilation, since quasistatic lung compliance was unchanged.