AIMTo investigate the influence of the vagus nerve on the electrophysiological properties in the Mauthner cell soma and the relationship between soma and viscus.

METHODSThe microelectrode recording technique was used to explore the electrophysiological properties in the Mauthner cell when stimulating the right vagus.

RESULTSAt lower stimulation strength a graded and compound excitatory postsynaptic potentials (EPSP), formed by two components with lower amplitude, were recorded on the Mauthner cell in a crucian carp. As the intensity of stimulus increased, the amplitude became larger and lasting time longer. With the stimulations high enough, action potentials (AP) were evoked on the EPSP.

CONCLUSION(1) Action potential can be induced on M cell by a direct stimulation on vagus nerve, which is in controversy with previous reports. (2) The neural pathway projecting from vagus to M cell is composed of a set of neuronal chains with excitatory and/or inhibitory members, the activation of M cell depends on the relationship between excitatory and inhibitory neuron.