RESUMO
This is a nonclinical, controlled, and triple-blind study to investigate the effects of codeine-associated geraniol on the modulation of orofacial nociception and its potential central nervous system depressing effect in an animal model. The orofacial antinociceptive activity of geraniol in combination with codeine was assessed through the following tests: (i) formalin-induced pain, (ii) glutamate-induced pain, and (iii) capsaicin-induced pain. Six animals were equally distributed into six groups and received the following treatments, given intraperitoneally (i.p.) 30 minutes before the experiments: a) geraniol/codeine 50/30 mg/kg; b) geraniol/codeine 50/15 mg/kg; c) geraniol/codeine 50/7.5 mg/kg; d) geraniol 50 mg/kg; e) codeine 30 mg/kg (positive control); or f) 0.9% sodium chloride (negative control). We performed pain behavior analysis after the injection of formalin (20 µL, 20%), glutamate (20 µL, 25 µM), and capsaicin (20 µL, 2.5 µg) into the paranasal region. Rubbing time of the paranasal region by the hind or front paw was used as a parameter. In the neurogenic phase of the formalin test, the geraniol/codeine at 50/7.5 mg/kg was able to promote the maximum antinociceptive effect, reducing nociception by 71.9% (p < 0.0001). In the inflammatory phase of the formalin test, geraniol/codeine at 50/30 mg/kg significantly reduced orofacial nociception (p < 0.005). In the glutamate test, geraniol/codeine at 50/30 mg/kg reduced the rubbing time by 54.2% and reduced nociception in the capsaicin test by 66.7% (p < 0.005). Geraniol alone or in combination does not promote nonspecific depressing effects on the central nervous system. Based on our findings, we suggest the possible synergy between geraniol and codeine in the modulation of orofacial pain.
Assuntos
Monoterpenos Acíclicos , Analgésicos , Capsaicina , Codeína , Dor Facial , Medição da Dor , Terpenos , Animais , Codeína/farmacologia , Dor Facial/induzido quimicamente , Dor Facial/tratamento farmacológico , Monoterpenos Acíclicos/farmacologia , Masculino , Medição da Dor/efeitos dos fármacos , Capsaicina/farmacologia , Terpenos/farmacologia , Analgésicos/farmacologia , Camundongos , Fatores de Tempo , Modelos Animais de Doenças , Reprodutibilidade dos Testes , Formaldeído , Ácido Glutâmico , Resultado do Tratamento , Nociceptividade/efeitos dos fármacos , Análise de Variância , Estatísticas não Paramétricas , Comportamento Animal/efeitos dos fármacosRESUMO
Sexual dimorphism among mammals includes variations in the pain threshold. These differences are influenced by hormonal fluctuations in females during the estrous and menstrual cycles of rodents and humans, respectively. These physiological conditions display various phases, including proestrus and diestrus in rodents and follicular and luteal phases in humans, distinctly characterized by varying estrogen levels. In this study, we evaluated the capsaicin responses in male and female mice at different estrous cycle phases, using two murine acute pain models. Our findings indicate that the capsaicin-induced pain threshold was lower in the proestrus phase than in the other three phases in both pain assays. We also found that male mice exhibited a higher pain threshold than females in the proestrus phase, although it was similar to females in the other cycle phases. We also assessed the mRNA and protein levels of TRPV1 in the dorsal root and trigeminal ganglia of mice. Our results showed higher TRPV1 protein levels during proestrus compared to diestrus and male mice. Unexpectedly, we observed that the diestrus phase was associated with higher TRPV1 mRNA levels than those in both proestrus and male mice. These results underscore the hormonal influence on TRPV1 expression regulation and highlight the role of sex steroids in capsaicin-induced pain.
Assuntos
Capsaicina , Dor , Canais de Cátion TRPV , Animais , Canais de Cátion TRPV/metabolismo , Canais de Cátion TRPV/genética , Capsaicina/farmacologia , Masculino , Feminino , Camundongos , Dor/metabolismo , Dor/genética , Hormônios Esteroides Gonadais/metabolismo , Ciclo Estral/efeitos dos fármacos , Limiar da Dor/efeitos dos fármacos , Gânglios Espinais/metabolismo , Gânglios Espinais/efeitos dos fármacos , Gânglio Trigeminal/metabolismo , Gânglio Trigeminal/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Caracteres Sexuais , RNA Mensageiro/metabolismo , RNA Mensageiro/genéticaRESUMO
Although TRPV1 receptors play an essential role in the adverse effects on the airways following captopril treatment, there is no available evidence of their involvement in treatment regimens involving repeated doses of captopril. Comparing the difference in these two treatment regimens is essential since captopril is a continuous-use medication. Thus, this study explored the role of the transient receptor potential vanilloid 1 (TRPV1) in the effects of captopril on rat airways using two treatment regimens. Airway resistance, bronchoalveolar lavage (BAL), and histological and immunohistochemical analyses were conducted in rats administered with single or repeated doses of captopril. This study showed that the hyperresponsiveness to bradykinin and capsaicin in captopril-treated rats was acute. Treatment with the selective B2 antagonist, HOE140 reduced bradykinin hyperresponsiveness and abolished capsaicin exacerbation in single-dose captopril-treated rats. Likewise, degeneration of TRPV1-positive neurones also reduced hyperresponsiveness to bradykinin. Single-dose captopril treatment increased leukocyte infiltration in the BAL when compared with the vehicle and this increase was reduced by TRPV1-positive neurone degeneration. However, when compared with the vehicle treatment, animals treated with repeated doses of captopril showed an increase in leukocyte influx as early as 1 h after the last captopril treatment, but this effect disappeared after 24 h. Additionally, an increase in TRPV1 expression occurred only in animals who received repeated captopril doses and the degeneration of TRPV1-positive neurones attenuated TRPV1 upregulation. In conclusion, these data strongly indicate that a treatment regimen involving multiple doses of captopril not only enhances sensitisation but also upregulates TRPV1 expression. Consequently, targeting TRPV1 could serve as a promising strategy to reduce the negative impact of captopril on the airways.
Assuntos
Bradicinina , Líquido da Lavagem Broncoalveolar , Capsaicina , Captopril , Canais de Cátion TRPV , Animais , Captopril/farmacologia , Canais de Cátion TRPV/metabolismo , Ratos , Masculino , Bradicinina/farmacologia , Capsaicina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Ratos Sprague-Dawley , Resistência das Vias Respiratórias/efeitos dos fármacos , Antagonistas de Receptor B2 da Bradicinina/farmacologia , Relação Dose-Resposta a Droga , Hiper-Reatividade Brônquica/induzido quimicamente , Hiper-Reatividade Brônquica/tratamento farmacológico , Neurônios/efeitos dos fármacos , Neurônios/metabolismoRESUMO
OBJECTIVE: This study aimed to investigate the effect of Esketamine (ESK) on the Hypoxia/Reoxygenation (H/R) injury of cardiomyocytes by regulating TRPV1 and inhibiting the concentration of intracellular Ca2+. METHODS: The H/R injury model of H9c2 cardiomyocytes was established after 4h hypoxia and 6h reoxygenation. H9c2 cells were treated with different concentrations of ESK or TRPV1 agonist capsaicin (10 µM) or TRPV1 inhibitor capsazepine (1 µM). Cell viability was detected by CCK-8 method, and apoptosis by flow cytometry. Intracellular Ca2+ concentration was evaluated by Fluo-4 AM. LDH, MDA, SOD, and GSH-Px were detected with corresponding commercial kits. TRPV1 and p-TRPV1 proteins were detected by Western blot. RESULTS: After H/R, H9c2 cell viability decreased, apoptosis increased, intracellular Ca2+ concentration increased, LDH and MDA levels increased, SOD and GSH-Px levels decreased, and p-TRPV1 expression increased. ESK treatment rescued these changes induced by H/R. After up-regulating TRPV1, the protective effect of ESK on H/R injury of H9c2 cells was weakened, while down-regulating TRPV1 could further protect against H/R injury. CONCLUSION: ESK alleviates H/R injury of cardiomyocytes by regulating TRPV1 expression and inhibiting intracellular Ca2+ concentration.
Assuntos
Apoptose , Cálcio , Capsaicina/análogos & derivados , Sobrevivência Celular , Ketamina , Miócitos Cardíacos , Canais de Cátion TRPV , Canais de Cátion TRPV/metabolismo , Canais de Cátion TRPV/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Animais , Ketamina/farmacologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Ratos , Capsaicina/farmacologia , Hipóxia Celular/efeitos dos fármacos , Linhagem Celular , Citometria de Fluxo , Estresse Oxidativo/efeitos dos fármacos , Western BlottingRESUMO
INTRODUCTION: It has been suggested that capsaicin (CAP), a major pungent component in chili peppers, can be used as an anti-obesity ingredient due to effects on energy metabolism, but evidence is not consistent. Genetics may account for differences in CAP tolerance and its impact on adiposity status. The aim of this study was to systematically review current evidence concerning the role of genetic polymorphisms influencing CAP tolerance. METHODS: The present systematic review analyzed and synthesized available evidence concerning associations between genetic polymorphisms and CAP tolerance following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines. Databases such as PubMed/MEDLINE, Cochrane, Scopus, Google Scholar, SciELO, and LILACS were screened. Out of 228 publications identified, only 6 meet inclusion criteria and were finally included in the final report. RESULTS: Overall, a total of 28 single nucleotide polymorphisms were associated with several CAP tolerance traits including sensitivity to burning/stinging, heat pain, and cough reactions, and detection of bitter taste thresholds. These genetic variants were located within 6 genes involved in key physiological processes such synthesis of tetrahydrobiopterin and nitric oxide production (GCH1), CAP uptake and transduction of thermal stimuli (TRPV1), and bitter taste perception (TAS2R38, TAS2R3, TAS2R4, and TAS2R5). CONCLUSION: There is evidence about the influence of genetic polymorphisms on CAP tolerance by affecting nociceptive signaling, CAP binding, and bitter tasting. This knowledge may facilitate the design and implementation of innovative CAP-based nutrigenetic strategies for a more precise clinical management of obesity.
Assuntos
Capsaicina , Obesidade , Polimorfismo de Nucleotídeo Único , Humanos , Capsaicina/farmacologia , Obesidade/genética , Capsicum/genética , Paladar/genética , Percepção Gustatória/genética , Canais de Cátion TRPV/genética , Medicina de PrecisãoRESUMO
The TRPV1 receptor, which is known to contribute significantly to pain perception, has recently been identified as a useful tool for predicting eye stinging potential in cosmetics. In this study, HEK-293 cells with high TRPV1 expression were utilized to evaluate calcium influx related to receptor activation triggered by chemicals and cosmetic formulations. The cells were exposed to increasing concentrations of substances to cause or not some aggression to the eye, and TRPV1 activity was assessed by measuring intracellular FURA-2 AM fluorescence signal. To confirm TRPV1 channel activation, capsazepine, a capsaicin antagonist, was employed in addition to using capsaicin as a positive control. The study's results indicate that this novel model can identify compounds known to cause some aggression to the eye, such as stinging, considering a cut-off value of 60% of Ca2+ influx exposed to the lowest evaluated concentration (0.00032%). When applied to the cosmetic baby formulation, although the presented model exhibited higher sensitivity by classifying as stinging formulations that had previously undergone clinical testing and were deemed non-stinging, the assay could serve as a valuable in vitro tool for predicting human eye stinging sensation and can be used as a tier 1 in an integrated testing strategy.
Assuntos
Cálcio , Cosméticos , Canais de Cátion TRPV , Humanos , Cosméticos/toxicidade , Células HEK293 , Canais de Cátion TRPV/metabolismo , Cálcio/metabolismo , Olho/efeitos dos fármacos , Capsaicina/análogos & derivados , Capsaicina/farmacologia , Alternativas aos Testes com AnimaisRESUMO
Psidium brownianum Mart is reported in the literature by antinociceptive and antioxidant activities, indicating that this species' secondary metabolites might be used to control inflammatory processes. The present study aimed to characterize the topical antiedematogenic activity of the essential oil of Psidium brownianum Mart. (OEPB) in ear edema models by different inflammatory agents. Female Swiss mice (25-35â g) and Wistar albino rats (200-300â g) were used throughout tests (n=6/group) on acute or chronic edema models induced by single and multiple topical applications. The OEPB is administered topically pure or at a concentration of 100 or 200â mg/mL. The antiedematogenic mechanism of OEPB was analyzed by administering capsaicin, arachidonic acid, histamine, and phenol at the best effective dose (200â mg/mL). The results showed a significant reduction of edema-induced single (28.87 %) and multiple (50.13 %) applications of croton oil compared to the negative control group. Regarding potential mechanisms of action, OEPB (200â mg/mL) inhibited the development of edema triggered by capsaicin (29.95 %), arachidonic acid (22.66 %), phenol (23.35 %), and histamine (75.46 %), suggesting an interference with the histaminergic pathway. These results indicate that OEPB presents a topical antiedematogenic effect in acute and chronic murine models, possibly interfering with inflammatory pathways triggered by mediators such as histamine.
Assuntos
Óleos Voláteis , Psidium , Camundongos , Feminino , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/uso terapêutico , Capsaicina , Histamina/efeitos adversos , Ácido Araquidônico/efeitos adversos , Edema/induzido quimicamente , Edema/tratamento farmacológico , Extratos Vegetais/farmacologiaRESUMO
BACKGROUND: Pannexin1 (Panx1) is a membrane channel expressed in different cells of the nervous system and is involved in several pathological conditions, including pain and inflammation. At the central nervous system, the role of Panx1 is already well-established. However, in the periphery, there is a lack of information regarding the participation of Panx1 in neuronal sensitization. The dorsal root ganglion (DRG) is a critical structure for pain processing and modulation. For this reason, understanding the molecular mechanism in the DRG associated with neuronal hypersensitivity has become highly relevant to discovering new possibilities for pain treatment. Here, we aimed to investigate the role of Panx1 in acute nociception and peripheral inflammatory and neuropathic pain by using two different approaches. METHODS: Rats were treated with a selective Panx1 blocker peptide (10Panx) into L5-DRG, followed by ipsilateral intraplantar injection of carrageenan, formalin, or capsaicin. DRG neuronal cells were pre-treated with 10Panx and stimulated by capsaicin to evaluate calcium influx. Panx1 knockout mice (Panx1-KO) received carrageenan or capsaicin into the paw and paclitaxel intraperitoneally. The von Frey test was performed to measure the mechanical threshold of rats' and mice's paws before and after each treatment. RESULTS: Pharmacological blockade of Panx1 in the DRG of rats resulted in a dose-dependent decrease of mechanical allodynia triggered by carrageenan, and nociception decreased in the second phase of formalin. Nociceptive behavior response induced by capsaicin was significantly lower in rats treated with Panx1 blockade into DRG. Neuronal cells with Panx1 blockage showed lower intracellular calcium response than untreated cells after capsaicin administration. Accordingly, Panx1-KO mice showed a robust reduction in mechanical allodynia after carrageenan and a lower nociceptive response to capsaicin. A single dose of paclitaxel promoted acute mechanical pain in wildtype (WT) but not in Panx1-KO mice. Four doses of chemotherapy promoted chronic mechanical allodynia in both genotypes, although Panx1-KO mice had significant ablation in the first eight days. CONCLUSION: Our findings suggest that Panx1 is critical for developing peripheral inflammatory pain and acute nociception involving transient receptor potential vanilloid subtype 1 (TRPV1) but is not essential for neuropathic pain chronicity.
Assuntos
Hiperalgesia , Neuralgia , Ratos , Camundongos , Animais , Hiperalgesia/induzido quimicamente , Hiperalgesia/tratamento farmacológico , Hiperalgesia/patologia , Capsaicina/farmacologia , Capsaicina/uso terapêutico , Paclitaxel/efeitos adversos , Carragenina/efeitos adversos , Cálcio , Neuralgia/induzido quimicamente , Neuralgia/tratamento farmacológico , Formaldeído/efeitos adversos , Gânglios Espinais , Proteínas do Tecido Nervoso , Conexinas/genética , Conexinas/uso terapêuticoRESUMO
In the 1990s, the identification of a non-selective ion channel, especially responsive to capsaicin, revolutionized the studies of somatosensation and pain that were to follow. The TRPV1 channel is expressed mainly in neuronal cells, more specifically, in sensory neurons responsible for the perception of noxious stimuli. However, its presence has also been detected in other non-neuronal cells, such as immune cells, ß- pancreatic cells, muscle cells and adipocytes. Activation of the channel occurs in response to a wide range of stimuli, such as noxious heat, low pH, gasses, toxins, endocannabinoids, lipid-derived endovanilloid, and chemical agents, such as capsaicin and resiniferatoxin. This activation results in an influx of cations through the channel pore, especially calcium. Intracellular calcium triggers different responses in sensory neurons. Dephosphorylation of the TRPV1 channel leads to its desensitization, which disrupts its function, while its phosphorylation increases the channel's sensitization and contributes to the channel's rehabilitation after desensitization. Kinases, phosphoinositides, and calmodulin are the main signaling pathways responsible for the channel's regulation. Thus, in this review we provide an overview of TRPV1 discovery, its tissue expression as well as on the mechanisms by which TRPV1 activation (directly or indirectly) induces pain in different disease models.
Assuntos
Neuroimunomodulação , Dor , Canais de Cátion TRPV , Humanos , Cálcio/metabolismo , Capsaicina/farmacologia , Dor/metabolismo , Canais de Cátion TRPV/metabolismo , AnimaisRESUMO
The habanero pepper (Capsicum chinense) is a prominent spicy fruit integral to the historical, social, cultural, and economic fabric of the Yucatan peninsula in Mexico. This study leverages the power of 1H NMR spectroscopy coupled with machine learning algorithms to dissect the metabolomic profile of eleven C. chinense cultivars, including those grown by INIFAP (Habanero-Jaguar, Antillano-HRA 1-1, Antillano-HRA 7-1, Habanero-HAm-18A, Habanero-HC-23C, and Jolokia-NJolokia-22) and commercial hybrids (Habanero-Rey Votán, Habanero-Kabal, Balam, USAPR10117, and Rey Pakal). A total of fifty metabolites, encompassing sugars, amino acids, short-chain organic acids, and nucleosides, were identified from the 1H NMR spectra. The optimized machine learning model proficiently predicted the similarity percentage between the INIFAP-grown cultivars and commercial hybrids, thereby facilitating a comprehensive comparison. Biomarkers unique to each cultivar were delineated, revealing that the Habanero-Rey Votán cultivar is characterized by the highest concentration of sugars. In contrast, the Balam cultivar is rich in amino acids and short-chain organic acids, sharing a similar metabolomic profile with the Jolokia-NJolokia-22 cultivar. The findings of this study underscore the efficacy and reliability of NMR-based metabolomics as a robust tool for differentiating C. chinense cultivars based on their intricate chemical profiles. This approach not only contributes to the scientific understanding of the metabolomic diversity among habanero peppers but also holds potential implications for food science, agriculture, and the culinary arts.