Abstract

Since many years the theophylline have been noted for their bronchodilator properties. Several studies have indicated an inhibitory action of theophylline on the late response following allergen challenge and his effect was demonstrated at lower plasma levels then the so called therapeutic range of 10-20 micrograms/ml. There is now evidence to suggest that theophylline has anti-inflammatory actions. It has been recently reported that low dose of theophylline reduces the number of activated eosinophils found in bronchial biopsies and decreases the number of activated CD.4-lymphocytes in the bronchoalveolar lavage fluid. It was detected that neutrophils, eosinophils and monocytes exclusively contain PDE-IV. In lymphocytes and alveolar macrophages PDE IV and PDE-III are present in different amounts and ratios. Functional studies comparing the influence of mono-selective (rolipram-PDE-IV; motopizone PDE-III) dual-selective (zardaverine) and non-selective (theophylline) on cell activation considered the participation of PDE isoenzymes present in the respective cells. In mast cells, macrophages, T-lymphocytes and eosinophils PDE-IV appears to be the predominant isoenzyme and inhibits cell activation and secretion. PDE-IV is also involved in inhibition of mediator release from epithelial cells and neuropeptides from sensory nerves.