Der Einfluß desP A CO 2 auf die Wirkung der Sinusnervenreizung bei intakten und ausgeschalteten Nn. vagi

Summary In rabbits rebreathing oxygen one carotid sinus nerve was stimulated repeatedly by electrical stimuli of constant intensity, both before and after inactivation of vagi by cold blocking or sectioning. In animals with intact vagi the reflex hyperpnea elicited by the nerve stimulation decreased only slightly with increasing hypercapnia. After inactivation of the vagi the stimulatory effect was, at normalP _{A CO 2}, mostly greater than in the intact condition. But with increasing hypercapnia the decrease of the reflex hyperpnea was generally steeper than in the intact preparation, sometimes reaching even lower values than before inactivation. The depressant effects of the stimulation on systemic blood pressure and heart rate were not distinctly changed by the increase ofP _{A CO 2}, neither with intact nor with inactivated vagi. It is concluded that the ventilatory effect of chemoreceptor afferents is modified both by centralP _{CO 2} and by vagal afferents.

Mit Unterstützung der Deutschen Forschungsgemeinschaft (Wi 165).