Quantification of neuropeptides (calcitonin gene-related peptide, substance P, neurokinin A, neuropeptide Y and vasoactive intestinal polypeptide) expressed in healthy and inflamed human dental pulp.
ABSTRACT To quantify the expression of calcitonin gene-related peptide (CGRP), substance P (SP), neurokinin A (NKA), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) in healthy and inflamed human dental pulp tissue.
Six pulp samples were obtained from teeth having a clinical diagnosis of acute irreversible pulpitis. Another 12 pulp samples were obtained from premolars where extraction was indicated for orthodontic purposes. In six of these premolar teeth inflammation was induced by mechanical pulp exposure prior to sample collection. All samples were processed and 125I-labelled; neuropeptides were quantified by competition assays. ANOVA and Mann-Whitney's (post hoc) tests were used to establish statistically significant differences between the groups.
Expression of five neuropeptides was found in all human pulp samples. Statistical analysis revealed a significantly higher (P < 0.05) expression of CGRP, SP, NKA and NPY in both inflammatory conditions compared with healthy pulp control values. VIP expression remained stable during the inflammatory conditions.
Expression of CGRP, SP and NKA released from C-fibres and NPY released from sympathetic fibres is significantly higher in the inflamed human pulp compared with healthy pulp. Expression of VIP released from parasympathetic fibres is not increased during the inflammatory conditions of human dental pulp.
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ABSTRACT: Neuropeptide Y (NPY) is an important modulatory neuropeptide that regulates several physiological systems, including the activity of sensory neurons. We evaluated whether activation of the NPY Y1 receptor could modulate the activity of capsaicin-sensitive nociceptors in trigeminal ganglia and dental pulp. We tested this hypothesis by measuring capsaicin-stimulated calcitonin gene-related peptide release (CGRP) as a measure of nociceptor activity. Capsaicin-evoked CGRP release was inhibited by 50% (p < 0.05) in trigeminal ganglia and by 26% (p < 0.05) in dental pulp when tissues were pre-treated with [Leu(31),Pro(34)]NPY. The Y1 receptor was found to co-localize with the capsaicin receptor TRPV1 in trigeminal ganglia. These results demonstrate that activation of the Y1 receptor results in the inhibition of the activity of capsaicin-sensitive nociceptors in the trigeminal ganglia and dental pulp. These findings are relevant to the physiological modulation of dental nociceptors by endogenous NPY and demonstrate an important novel analgesic target for the treatment of dental pain.Journal of dental research 10/2008; 87(10):948-52. · 3.46 Impact Factor
Article: Tear levels of neuropeptides increase after specific allergen challenge in allergic conjunctivitis.[show abstract] [hide abstract]
ABSTRACT: Growing evidence is showing a role of neurogenic inflammation in allergic reactions, with sensory and autonomic nerve fibers releasing neuromediators, which may actively participate in the allergic inflammatory cascade. Although the cornea is the most densely innervated tissue of the human body, little is known on the role of neuromediators at the ocular surface. In this study, we aimed at evaluating the role of substance P (SP), calcitonine gene related peptide (CGRP), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) in allergic reactions of the ocular surface. Fifteen patients with allergic conjunctivitis (6 female, 9 male, mean age 30±8 years) in non-active phase, and 10 age-matched healthy subjects were included in this study. The conjunctival provocation test (CPT) with allergen was performed in all allergic patients and in 5 healthy subjects. Tear samples were collected and the tear content of VIP, NPY, CGRP, and SP was measured by ELISA at baseline and after CPT. The Mann-Whitney U-test and Wilcoxon test were used to compare neuromediator tear levels. No significant differences in neuropeptide tear levels were observed between healthy and allergic patients in non-active phase. CPT induced conjunctival hyperemia and itching in all allergic patients, while no reaction was observed in the control eyes and in healthy subjects. In allergic patients SP, CGRP, and VIP, but not NPY, were significantly higher after CPT as compared to baseline (SP: 3.9±1.3 ng/ml versus 5.8±1.1 ng/ml, p=0.011; CGRP: 5.5±2.3 ng/ml versus 7.3±2.7 ng/ml; p=0.002; VIP: 4±0.9 ng/ml versus 5.1±1.5 ng/ml, p=0.007). No significant changes were observed in the control eyes of allergic patients challenged with diluent and in healthy subjects after allergen provocation. Locally-released neuromediators may participate in modulating the allergic response of the ocular surface.Molecular vision 01/2011; 17:47-52. · 2.20 Impact Factor
Article: Tooth sensitivity and bleaching effectiveness associated with use of a calcium-containing in-office bleaching gel.[show abstract] [hide abstract]
ABSTRACT: The authors conducted a study to evaluate tooth sensitivity (TS) and the bleaching effectiveness associated with use of a calcium-containing (CC) in-office bleaching gel. The authors used a 35 percent calcium-free (CF) hydrogen peroxide gel and a 35 percent CC hydrogen peroxide gel according to the manufacturer's instructions in 40 caries-free participants 18 years or older. They performed two bleaching sessions with a one-week interval between sessions. The authors registered the color at baseline and after the first and second bleaching sessions by using a shade guide and by gauging the participant's perception of TS as registered on a scale from 0 (none) to 4 (severe). The authors evaluated the bleaching effectiveness at each week's recall visit by means of the Friedman test, and they compared the groups at each assessment point by means of the Mann-Whitney test. They evaluated the percentage of participants with TS and the intensity of the TS by using the Fisher exact and Mann-Whitney tests. Both groups demonstrated equivalent and significant tooth color enhancement compared with color values at baseline (P < .05), with an average bleaching of 7 to 8 shade guide units. Most of the participants from the CF group (80 percent) experienced sensitivity while undergoing the bleaching regimen, whereas only 40 percent of participants from the CC group reported experiencing TS (P = .02). The intensity of TS was significantly higher (P < .01) for the CF group during in-office dental bleaching. The CC 35 percent hydrogen peroxide gel reduced the TS during in-office dental bleaching without jeopardizing the bleaching effectiveness. The results of this study support the findings that a CC 35 percent hydrogen peroxide gel can reduce TS during in-office dental bleaching.Journal of the American Dental Association (1939) 12/2012; 143(12):e81-7. · 1.77 Impact Factor