ABSTRACT
After the bilateral phrenic nerves of the dogs were stimulated,the effect of amino-phylline on the function of normal and fatigued diaphragm was observed with the determination of transdiaphragmatic pressure-stmulation frequency curve (Pdi-F).and the analysis of the power spectrum of diaphragmatic electromyogram (DMGdi) at spontaneous breathing.After the administration of 10 and 20 mg/kg of aminophylline ,the PDi pf the normal diaphragm was increased and that of the fatigued diaphragm recovered.The Pdi-F curve of the fatigued diaphragm was shifted to the left,and the central frequency,the medium frequency,and the high/low frequency ratio were markedly increased.It is concluded that aminophylline at the therapeutic dosage can imporve the generation of the strength and enhance the recovery of the fatigued diaphragm.