Histochemical demonstration of peripheral autonomic innervation in canine nasal mucosa by retrograde axonal transport of horseradish perioxidase.

The peripheral autonomic nervous pathways of the nasal mucosa in dogs were investigated by the horseradish peroxidase (HRP) method. HRP was applied to the nasal mucosa, caudal nasal nerve, ethmoidal nerve, vidian nerve and pterygopalatine ganglion in 20 dogs, and retrogradely labelled neurons were observed in the superior cervical ganglion (SCG) and the pterygopalatine ganglion (PPG) by the blue reaction method. It was suggested that the vidian nerve, the maxillary branch of the trigeminal nerve, the caudal nasal nerve, the pterygopalatine nerve and the ethmoidal nerve contained the postganglionic sympathetic fibres which originated in SCG and terminated in the nasal mucosa. Moreover, other sympathetic pathways, such as those around the blood vessels, were also suggested to be a main route. It was suggested that the postganglionic parasympathetic fibers originating in PPG travelled along the caudal nasal nerve and the ethmoidal nerve.