[Modulation of reflex discharges in the respiratory nerves of the cat upon stimulation of superior laryngeal afferents].

Cyclic changes of reflex discharges in phrenic, external and internal intercostal and lumbar nerves evoked by electrical stimulation of the superior laryngeal nerve were investigated in cats under light nembutal anaesthesia. Intensity of discharges and their latency varied in different nerves during the respiratory cycle. Reflex discharges of the greatest intensity with the shortest latency appeared at the end of the inspiratory or at the beginning of the expiratory phase in lumbar and internal intercostal nerves. Significant or complete depression of reflex discharges was observed before the inspiratory phase in these nerves. In contrast, reflex discharges in the phrenic and external intercostal nerves appeared only during the inspiratory phase and their intensity increased towards the end of this phase. Pronounced modulation of reflex discharges depended directly on changes in the respiratory centre excitability.