In:
Journal of Periodontology, Wiley, Vol. 80, No. 5 ( 2009-05), p. 850-859
Abstract:
Background: The extracellular signal‐regulated kinases 1 and 2 (ERK1/2) have been implicated in the inflammation‐dependent sensitization of nociceptors. Because the periodontal ligament (PDL) contains numerous nociceptors and mechanoceptors, phosphorylation of ERK1/2 was investigated in nerve fibers of the PDL to elucidate the role of constitutive local activation of ERK1/2 in peripheral sensitization. Methods: Decalcified free‐floating sections of rat molars with PDL were incubated using total (t)‐ERK1/2 and phosphorylated (p)‐ERK1/2 antibodies. For identification of nerve fibers in the PDL, double staining was performed using protein gene product 9.5 (PGP 9.5) with p‐ERK1/2. To test whether p‐ERK1/2 activated in sensory and mechanoreceptive terminals, double incubations were performed using p‐ERK1/2 with calcitonin gene‐related peptide (CGRP) and with calretinin. Labeled nerve fibers were quantified by the point‐counting method. Results: In cervical, midroot, and apical zones of the PDL, t‐ERK1/2– and p‐ERK1/2–labeled nerve fibers were found in close association with blood vessels. The p‐ERK1/2–labeled free nerve fibers were often detected in cervical and apical areas of the PDL. In nerve fibers of the PDL, p‐ERK1/2 was colocalized with PGP 9.5, CGRP, and calretinin. Conclusions: The perivascular distribution of t‐ERK1/2 and p‐ERK1/2 in nerve fibers in the PDL is compatible with a role for the constitutive activation of ERK1/2 in the neural regulation of blood vessels in the PDL. The colocalizations of p‐ERK1/2 with CGRP and calretinin indicate that ERK1/2 is constitutively activated in a subpopulation of sensory and mechanoreceptive nerve terminals in the PDL.
Type of Medium:
Online Resource
ISSN:
0022-3492
,
1943-3670
DOI:
10.1902/jop.2009.080550
Language:
English
Publisher:
Wiley
Publication Date:
2009
detail.hit.zdb_id:
2040047-0
