P723

         Eur Respir J 1990 Mar ; 3 (3) : 311-7

        Aminophylline enhances ventilation in phrenicotomized rats.

        Nacházel J, Paleček F.

        Institute of Pathophysiology, Faculty of Pediatrics, Charles University,

        Praha, Czechoslovakia.

        The aim was to test the effects of aminophylline (AP) on breathing of

        phrenicotomized rats. Fifty seven male rats of the Wistar strain were

        anaesthetized with 1.3 g.kg-1 urethane i.p. They were phrenicotomized,

        divided into 6 groups and given 5, 10, 20, 40 and 80 mg.kg-1 AP i.v. or

        a corresponding volume of saline. Ventilation, tracheal occlusion

        pressure and arterial blood gases were measured. In all animals

        phrenicotomy resulted in hypoventilation with corresponding hypoxaemia

        (from control 11.9  1.0 to 10.4  0.8 kPa) and hypercapnia (from

        control 4.6  0.5 to 5.5  0.6 kPa). In the control group (with

        saline) 4 h later the PaO2 was 8.6  1.1 kPa and PaCO2 7.2  0.6

        kPa. After AP 1 h after phrenicotomy the minute ventilation increased in

        a dose-dependent manner by 1-66%. 4 h after phrenicotomy the minute

        ventilation of rats with 20 and 40 mg.kg-1 of AP was significantly

        higher than that of the control group. AP prevented hypoventilation when

        injected into phrenicotomized rats. The results give no unequivocal

        basis from which to decide the proportion of central and peripheral

        effects of AP.