Preserved vagal visceromotor function following destruction of the dorsal motor nucleus.

1. The dorsal motor nucleus of the vagus was destroyed in cats and after survival periods greater than 10 days, the response of the heart, bronchioles, oesophagus and duodenum to electrical stimulation of the cervical vagi was investigated. The responses obtained from the vagus ipsilateral to the destroyed dorsal motor nucleus were compared to those obtained from the contralateral vagus and with normal controls. No significant differences were demonstrable.2. The responses obtained from stimulation of the cervical vagus following chronic intracranial rhizotomy of the IXth, Xth and XIth nerves were also examined. Visceromotor responses were abolished in three experiments and atypical responses were obtained in two experiments.3. It is concluded that the dorsal motor nucleus does not supply the vagal fibres which produce contraction of the smooth muscle of the bronchioles, oesophagus and duodenum, and that it is not the source of the cardio-inhibitory fibres4. A simple method of destroying a longitudinal column of neurones is described.