There is increasing evidence that diabetes may be related to sensory changes in the trigeminal system. Long lasting facial heat hyperalgesia has been described in diabetic rats, but the mechanisms remain to be elucidated. Herein, the contribution of peripheral and central TRPV1 receptors to facial heat hyperalgesia in diabeticrats was investigated. Diabetes was induced in male Wistar rats by streptozotocin (60mg/kg, i.p) and facial heat hyperalgesia was assessed once a week up to four weeks. The role of TRPV1 receptors in the heat hyperalgesia in diabetic rats was evaluated through: 1) the ablation of TRPV1 receptors by resiniferatoxin (RTX) treatment and 2) injection of the TRPV1 antagonist, capsazepine, into the upper lip, trigeminal ganglion or medullary subarachnoid space, at doses that completed prevented the heat hyperalgesia induced by capsaicin in naïve rats. Western blot was used to estimate the changes in TRPV1 expression in diabetic rats. Diabetic rats exhibited facial heat hyperalgesia from the first up to the fourth week after streptozotocin injection, which was prevented by insulin treatment. Ablation of TRPV1-expressing fibers prevented facial hyperalgesia in diabetic rats. Capsazepine injection in all sites resulted in significant reduction of facial heat hyperalgesia in diabetic rats. Diabetic rats exhibited a significant decrease in TRPV1 expression in the trigeminal nerve, increased expression in the trigeminal ganglion and no changes in subnucleus caudalis when compared to normoglycemic ones. In conclusion, our results suggest that facial heat hyperalgesia in diabetic rats is maintained by peripheral and central TRPV1 receptors activation.
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http://dx.doi.org/10.1016/j.brainres.2017.06.004 | DOI Listing |
Physiol Behav
December 2024
Laboratory of Neuroanatomy and Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Av. Bandeirantes 3900, Ribeirão Preto, São Paulo,14049-900, Brazil; Behavioural Neurosciences Institute (INeC), Av. Bandeirantes 3900, Ribeirão Preto, 14040-900, São Paulo, Brazil. Electronic address:
Pain is a multifactorial debilitating condition associated with some psychiatric comorbidities such as generalized anxiety and depression. Concerning pharmacological treatment, which is often inefficient or associated with intense side effects, the physical and social context may be fundamental for patient's health improvement. In this sense, we sought to assess the impact of an enriched environment (EE) on neuropathic pain (NP) and depression comorbid.
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December 2024
Program in Dental Biomedical Sciences, School of Dentistry, University of Maryland Baltimore, Baltimore, MD, United States.
Temporomandibular disorder (TMD) is the most prevalent painful condition in the craniofacial area. Recent studies have suggested that external or intrinsic trauma to the temporomandibular joint (TMJ) is associated with the onset of painful TMD in patients. Here, we investigated the effects of TMJ trauma through forced-mouth opening (FMO) in mice to determine pain behaviors and peripheral sensitization of trigeminal nociceptors in both sexes.
View Article and Find Full Text PDFInt J Pharm
January 2025
Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India. Electronic address:
Chemotherapy-induced peripheral neuropathy (CIPN) is triggered by clinically recommended chemotherapeutics. Topical capsaicin (CAP) is a US-FDA-approved therapeutic entity for the mitigation of CIPN. Besides good skin permeation efficiency, CAP concentration in a topical dermal dosage form must be controlled due to its dose-dependent therapeutic and adverse effects.
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September 2024
Molecular, Cellular and Biochemical Pharmacology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
Early life stress (ELS) is associated with an increased risk of experiencing chronic pain during adulthood, but surprisingly little is known about the short-term influence of ELS on nociceptive processing in the immature nervous system and the concomitant effects on somatosensation in the neonate. Here, we investigate how ELS modulates pain in neonatal mice and the transcriptional and electrophysiological signatures of immature dorsal root ganglia (DRG). Shortly after the administration of a neonatal limiting bedding (NLB) paradigm from postnatal days (P)2 to P9, both male and female pups exhibited robust hypersensitivity in response to tactile, pressure, and noxious cold stimuli compared with a control group housed under standard conditions, with no change in their sensitivity to noxious heat.
View Article and Find Full Text PDFExp Parasitol
December 2024
University of Balamand, Faculty of Arts and Sciences, Lebanon.
Cutaneous leishmaniasis caused mainly by Leishmania major (L. major) is one of the trending models used to investigate induced hyperalgesia and the involved cytokines. Previous studies approached the role of several cytokines in the observed hyperalgesia, but the molecular mechanisms orchestrating such a response still needed to be addressed.
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