Differential TRPV1 and TRPV2 channel expression in dental pulp

Hypersensitivity to thermal and mechanical stimuli can occur in painful pulpitis. to explore the neuro-anatomical basis of heat and mechanical sensitivity,we evaluated expression of trpv1 (heat) and trpv2 (heat/mechanical) channels in the cell bodies and terminal arborizations of neurons that innervate the dental pulp (dp) and periodontal tissues (pdl). we report that ∼50% of trigeminal ganglion (tg) neurons retrogradely labeled from the dp express trpv2,and this was significantly greater than the general expression of this channel in the tg (15%) and slightly more than what is expressed in the pdl by retrograde labeling (40%). the trpv1 receptor,however,was less prevalent in neurons innervating the dp than their general expression in the tg (17% vs. 26%) and was more extensively expressed in neurons innervating the pdl (26%). co-labeling studies showed that 70% of neurons that innervate the dp are myelinated. approximately 1/3 of the retrogradely labeled neurons from the dp were calcitonin-gene-related-peptide-positive (peptide-expressing),but very few expressed the ib4 marker of non-peptidergic unmyelinated afferents. these findings suggest that the dp has a unique neurochemical innervation with regard to trp receptor expression,which has significant implications for the mechanisms contributing to odontogenic pain and management strategies. © 2011 international & american associations for dental research.