The distal vagal ganglion of the hen (Gallus domesticus). A histological and physiological study.

The distal vagal ganglion of the hen was examined histologically and physiologically. The number of neurons in the right and left distal vagal ganglia were counted and a mean figure of 6710 neurons obtained. The proportions of the different types of neuron present were determined and their size measured. No multipolar cells with boutons on them were found. Morphologically the ganglion is sensory. Following chronic vagotomy proximal to the distal vagal ganglion the vagus nerves were stimulated and the effect on the heart and gastrointestinal tract monitored. It was found that stimulation of the acutely sectioned nerve caused a drop in heart rate and an increase in gastrointestinal activity. There was no cardiac or gastrointestinal response when the chronically operated nerve was stimulated. Physiologically the ganglion is sensory. The evidence is reviewed for homology between inferior vagal ganglion of the mammal and the distal vagal ganglion of the hen.