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. 2010 Jun 8:11:71.
doi: 10.1186/1471-2202-11-71.

Sodium channel Na v 1.7 immunoreactivity in painful human dental pulp and burning mouth syndrome

Kiran Beneng  1 , Tara Renton, Zehra Yilmaz, Yiangos Yiangou, Praveen Anand
Affiliations

Sodium channel Na v 1.7 immunoreactivity in painful human dental pulp and burning mouth syndrome

Kiran Beneng et al. BMC Neurosci. .

Abstract

Background: Voltage gated sodium channels Na v 1.7 are involved in nociceptor nerve action potentials and are known to affect pain sensitivity in clinical genetic disorders.

Aims and objectives: To study Na v 1.7 levels in dental pulpitis pain, an inflammatory condition, and burning mouth syndrome (BMS), considered a neuropathic orofacial pain disorder.

Methods: Two groups of patients were recruited for this study. One group consisted of patients with dental pulpitis pain (n = 5) and controls (n = 12), and the other patients with BMS (n = 7) and controls (n = 10). BMS patients were diagnosed according to the International Association for the Study of Pain criteria; a pain history was collected, including the visual analogue scale (VAS). Immunohistochemistry with visual intensity and computer image analysis were used to evaluate levels of Na v 1.7 in dental pulp tissue samples from the dental pulpitis group, and tongue biopsies from the BMS group.

Results: There was a significantly increased visual intensity score for Na v 1.7 in nerve fibres in the painful dental pulp specimens, compared to controls. Image analysis showed a trend for an increase of the Na v 1.7 immunoreactive % area in the painful pulp group, but this was not statistically significant. When expressed as a ratio of the neurofilament % area, there was a strong trend for an increase of Na v 1.7 in the painful pulp group. Na v 1.7 immunoreactive fibres were seen in abundance in the sub-mucosal layer of tongue biopsies, with no significant difference between BMS and controls.

Conclusion: Na v 1.7 sodium channel may play a significant role in inflammatory dental pain. Clinical trials with selective Na v 1.7 channel blockers should prioritize dental pulp pain rather than BMS.

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Figures

Figure 1
Figure 1
Immunoreactive nerve fibres in non-painful (left column) and painful (right column) human tooth pulp sections, within the subodontoblastic plexus region. Staining with antibodies to Nav1.7 (Figures 1a and 1c) and neurofilament cocktail (Figures 1b and 1d). Magnification × 40.
Figure 2
Figure 2
Visual intensity score of Nav1. 7 in tooth pulp (mean ± SEM). * P < 0.005.
Figure 3
Figure 3
Image analysis of control and painful tooth pulp using antibodies to Nav1.7 (Figure 3a), neurofilament (Figure 3b) and expressing the results as a ratio of Nav1.7:NFL (Figure 3c).
Figure 4
Figure 4
Immunoreactive Nav1.7 nerve fibres in control tongue (Figure 4a) and burning mouth syndrome (Figure 4b), magnification × 40. The bar charts (Figure 4c) show the image analysis and visual intensity scores (Figure 4d) of the Nav1.7 fibres in tongue (Mean ± SEM).
See this image and copyright information in PMC

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