VRL-I immunoreactivity in the rat cranial autonomic ganglia

Immunohistochemistry for VRL-I, a newly cloned capsaicin-receptor homologue, was performed on the rat cranial autonomic ganglia. The immunoreactivity (ir) was detected in the majority of neurones in the pterygopalatine (66%) and submandibular ganglia (68%). In the tongue and carotid body, parasympathetic neurones contained VRL-I ir. In the superior cervical ganglion, only 2% of postganglionic sympathetic neurones showed the immunoreactivity. VRL-I-ir nerve endings could not be detected in their peripheral tissues. These findings may suggest that VRL-I has functions within neuronal cell bodies of the cranial autonomic ganglia.