Vanilloid receptor 1 expression in human tooth pulp in relation to caries and pain.
OBJECTIVE
To investigate the presence of vanilloid receptor 1 (TRPV1) in human dental pulp and to correlate any expression with caries and pain.


METHODS
Permanent mandibular first molars were collected and categorized as intact or grossly carious. Grossly carious teeth were further categorized as carious asymptomatic or carious painful samples. Coronal pulps were removed and processed for indirect immunofluorescence using antibodies raised against TRPV1 and a neuronal marker, either protein gene product 9.5 or alpha-smooth muscle actin, in conjunction with Ulex europaeus agglutinin 1 lectin to fully label the pulp vasculature.


RESULTS
Analysis revealed that TRPV1 labeling was not confined to pulpal nerve fibers. TRPV1 was also consistently expressed within pulp microvasculature. Expression of neuronal TRPV1 was significantly increased throughout the pulp in grossly carious samples (P < .05). No significant differences were found between carious asymptomatic and carious painful samples. A significant increase in vascular TRPV1 expression was observed in arterioles present in the midcoronal pulp in carious painful compared with carious asymptomatic samples (mean area +/- SEM [%] of TRPV1 to vascular labeling; 6.48% +/- 4.5% for carious asymptomatic teeth, n = 9; 31.21% +/- 9.6% for carious painful teeth, n = 9; P = .02).


CONCLUSIONS
Expression of TRPV1 in pulpal nerve fibers undergoes marked changes with caries. This may be of relevance in the development of pulpal inflammation, but its relationship to dental pain is still unclear. However, vascular TRPV1 expression does appear to be positively correlated with dental pain, thus providing new insights into symptomatic pulpitis.
Morgan
Claire R
CR
School of Clinical Dentistry, University of Sheffield, Sheffield, South Yorkshire S10 2TA, United Kingdom. C.R.Morgan@sheffield.ac.uk
Rodd
Helen D
HD
Clayton
Nick
N
Davis
John B
JB
Boissonade
Fiona M
FM
D001808:Blood Vessels / Q000737:chemistry; D002648:Child; D003731:Dental Caries / Q000378:metabolism*; D003782:Dental Pulp / Q000098:blood supply / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008963:Molar; D011955:Receptors, Drug / Q000032:analysis*; D014098:Toothache / Q000378:metabolism*
D011955:Receptors, Drug