Journal of dental research
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Curcumin has diverse therapeutic effects, such as anti-inflammatory, anti-oxidant, anti-cancer, and antimicrobial activities. The vanilloid moiety of curcumin is considered important for activation of the transient receptor potential vanilloid 1 (TRPV1), which plays an important role in nociception. However, very little is known about the effects of curcumin on nociception. ⋯ Intraperitoneally administered curcumin blocked capsaicin-induced thermal hyperalgesia in a dose-dependent manner. Whereas curcumin reduced capsaicin-induced currents in a dose-dependent manner in both trigeminal ganglion neurons and TRPV1-expressing HEK 293 cells, curcumin did not affect heat-induced TRPV1 currents. Taken together, our results indicate that curcumin blocks capsaicin-induced TRPV1 activation and thereby inhibits TRPV1-mediated pain hypersensitivity.
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Odontoblasts function as mechanosensory receptors because of the expression of mechanosensitive channels in these cells. However, it is unclear if odontoblasts direct the signal transmission evoked by heat/cold or osmotic changes. This study investigated the effects of heat/cold or osmotic changes on calcium signaling and the functional expression of the thermo/mechanosensitive transient receptor potential (TRP) channels in primary cultured mouse odontoblastic cells, with the use of RT-PCR, fluorometric calcium imaging, and electrophysiology. ⋯ The receptor-specific stimulation of TRPV1-3 (heat-sensing receptors) and TRPV4/ TRPM3 (mechanic receptors) caused increases in the intracellular calcium concentration. Moreover, the channel activities of TRPV1-4 and TRPM3 were confirmed by a whole-cell patch-clamp technique. These results suggest that primary cultured mouse odontoblasts express heat/mechanosensitive TRP channels and play a role in the underlying mechanisms of thermo/mechanosensitive sensory transmission.
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Comparative Study
Distinct gender-related sleep pattern in an acute model of TMJ pain.
Since it is recognized that acute inflammation of the temporomandibular joint results in sleep disturbances in male rats, and that the orofacial region may display a site-specific effect of ovarian hormones on nociception, we hypothesized that distinct genders would respond differently when subjected to this inflammatory acute orofacial pain. Sleep was monitored after injection of saline/Freund's adjuvant into the temporomandibular joint in male and female (proestrus and diestrus phases) rats. ⋯ Behavior and sleep architecture in the females remained unaffected. Our results suggest that females and males present distinct responses to an acute model of orofacial pain.
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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. ⋯ 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.
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In clinical practice, oral appliances are used primarily for obstructive sleep apnea patients who do not respond to continuous positive airway pressure (CPAP) therapy. We hypothesized that an oral appliance is not inferior to CPAP in treating obstructive sleep apnea effectively. We randomly assigned 103 individuals to oral-appliance or CPAP therapy. ⋯ The lower boundary of the confidence interval was -21.7%, indicating that oral-appliance therapy was not inferior to CPAP for effective treatment of obstructive sleep apnea. However, subgroup analysis revealed that oral-appliance therapy was less effective in individuals with severe disease (apnea-hypopnea index > 30). Since these people could be at particular cardiovascular risk, primary oral-appliance therapy appears to be supported only for those with non-severe apnea.