The co-expression of P2X3 receptor with VR1 and VRL-1 in the rat trigeminal ganglion.
The co-expression of P2X3 receptor with the vanilloid receptor subtype I (VR1) and vanilloid receptor 1-like receptor (VRL-1) was examined in the rat trigeminal ganglion (TG) by a double immunofluorescence method. P2X3 receptor-immunoreactive (ir) neurons were predominantly small to medium-sized (range=93.8-1844.4 microm(2), mean+/-S.D.=503.8+/-286.5 microm(2)); 35% and 9% of P2X3 receptor-ir TG neurons were immunoreactive for VR1 and VRL-1, respectively. Small and medium-sized P2X3 receptor-ir neurons contained VR1-immunoreactivity (ir), whereas medium-sized and large P2X3 receptor-ir neurons showed VRL-1-ir. The retrograde tracing and immunohistochemical methods revealed that 30% of the TG neurons retrogradely labeled from the facial skin and tooth pulp exhibited P2X3 receptor-ir. The co-expression of P2X3 receptor and VR1 was detected in 16% of cutaneous TG neurons and 6% of tooth pulp neurons. On the other hand, the co-expression of P2X3 receptor and VRL-1 was common in tooth pulp neurons (23%) and rare in cutaneous TG neurons (8%). In the tooth pulp, 95% of P2X3 receptor-ir TG neurons contained VRL-1-ir. The present study indicates that P2X3 receptor-ir TG neurons, which co-express VR-ir, are abundant in the facial skin. The tooth pulp is probably innervated by TG neurons, which contain both P2X3-and VRL-1-ir.
Ichikawa
Hiroyuki
H
Department of Oral Function and Anatomy, and Biodental Research Center, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8525, Japan. hiroichi@md.okayama-u.ac.jp
Sugimoto
Tomosada
T
D000818:Animals; D002452:Cell Count; D048429:Cell Size; D003786:Dental Pulp Cavity / Q000294:innervation / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D015870:Gene Expression; D007150:Immunohistochemistry; D007473:Ion Channels; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058477:Receptors, Purinergic P2X3; D012867:Skin / Q000294:innervation / Q000378:metabolism; D013266:Stilbamidines / Q000378:metabolism; D050916:TRPV Cation Channels; D012668:Trigeminal Ganglion / Q000378:metabolism*
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D005456:Fluorescent Dyes; D007473:Ion Channels; C546410:P2rx3 protein, rat; D011955:Receptors, Drug; D018048:Receptors, Purinergic P2; D058477:Receptors, Purinergic P2X3; D013266:Stilbamidines; D050916:TRPV Cation Channels; C476722:Trpv2 protein, rat