The co-expression of VR1 and VRL-1 in the rat vagal sensory ganglia

Immunohistochemistry for two nociceptive transducers, the vanilloid receptor 1 (VR1) and vanilloid receptor 1-like receptor (VRL-1), was performed on the vagal sensory ganglia. In the jugular ganglion, VR1-immunoreactive (IR) neurons were small to medium-sized (range 49.7-1125.6 mum(2), mean+/-S.D. 407.7+/-219.7 mum(2)), whereas VRL-1-IR neurons were medium-sized to large (range 223.6-1341.1 mum(2), mean+/-S.D. 584.3+/-253.5 mum(2)). In the nodose ganglion,VR1- and VRL-1-IR neurons were mostly small to medium-sized (VR1: range 148.5-1464.4 mum(2), mean+/-S.D. 554.3+/-207.4 mum(2); VRL-1: range 161.7-1166.2 mum(2), mean+/-S.D. 541.9+/-186.2 mum(2)). The double immunofluorescence method revealed that co-expression of VR1-immunoreactivity among VRL-1-1R neurons was more abundant in the nodose ganglion (63%) than in the jugular ganglion (4%). The present study suggests that co-expression of VR1 and VRL-1 may be more common in visceral sensory neurons than in somatic sensory neurons. (C) 2003 Elsevier B.V. All rights reserved.