Metabolomics in human SGBS cells as new approach method for studying adipogenic effects: Analysis of the effects of DINCH and MINCH on central carbon metabolism.

Growing evidence suggests that exposure to certain metabolism-disrupting chemicals (MDCs), such as the phthalate plasticizer DEHP, might promote obesity in humans, contributing to the spread of this global health problem. Due to the restriction on the use of phthalates, there has been a shift to safer declared substitutes, including the plasticizer diisononyl-cyclohexane-1,2-dicarboxylate (DINCH). Notwithstanding, recent studies suggest that the primary metabolite monoisononyl-cyclohexane-1,2-dicarboxylic acid ester (MINCH), induces differentiation of human adipocytes and affects enzyme levels of key metabolic pathways. Given the lack of methods for assessing metabolism-disrupting effects of chemicals on adipose tissue, we used metabolomics to analyze human SGSB cells exposed to DINCH or MINCH. Concentration analysis of DINCH and MINCH revealed that uptake of MINCH in preadipocytes was associated with increased lipid accumulation during adipogenesis. Although we also observed intracellular uptake for DINCH, the solubility of DINCH in cell culture medium was limited, hampering the analysis of possible effects in the µM concentration range. Metabolomics revealed that MINCH induces lipid accumulation similar to peroxisome proliferator-activated receptor gamma (PPARG)-agonist rosiglitazone through upregulation of the pyruvate cycle, which was recently identified as a key driver of de novo lipogenesis. Analysis of the metabolome in the presence of the PPARG-inhibitor GW9662 indicated that the effect of MINCH on metabolism was mediated at least partly by a PPARG-independent mechanism. However, all effects of MINCH were only observed at high concentrations of 10 µM, which are three orders of magnitudes higher than the current concentrations of plasticizers in human serum. Overall, the assessment of the effects of DINCH and MINCH on SGBS cells by metabolomics revealed no adipogenic potential at physiologically relevant concentrations. This finding aligns with previous in vivo studies and supports the potential of our method as a New Approach Method (NAM) for the assessment of adipogenic effects of environmental chemicals.

Gabapentin improves neuropathic pain in Minamata disease model rats.

BACKGROUND: Methylmercury (MeHg), the causative agent of Minamata disease, damages the cranial nervous system and causes specific sensory disturbances, especially hypoesthesia, in the extremities. However, recent reports demonstrate that patients with chronic Minamata disease conversely develop neuropathic pain in the lower extremities. Studies on our established Minamata disease model rats showed that MeHg-mediated neurodegeneration might induce neuropathic pain by over time through inducing rewiring with neuronal activation in the somatosensory cortex via microglial activation in the spinal dorsal horn. METHODS: In this study, the effects of gabapentin, a potentially effective treatment for neuropathic pain, was evaluated using this Minamata disease model rats. To further elucidate the mechanism of its medicinal effects, histochemical and biochemical analyses of the nervous system of Minamata disease model rats were conducted. RESULTS: Gabapentin treatment restored the reduction in the pain threshold caused by MeHg exposure in rats. Histochemical and biochemical analyses revealed that gabapentin showed no effect on MeHg-induced neurodegeneration in entire nervous system and microglial activation in the spinal dorsal horn. However, it was shown that gabapentin may reduce excessive synaptogenesis through its antagonist action on the alpha2-delta-1 subunit of calcium channels in the somatosensory cortex. CONCLUSIONS: These results indicate that gabapentin may alleviated neuropathic pain in MeHg poisoning, as typified by Minamata disease, by reversibly modulation synaptic rewiring in the somatosensory cortex.

An experimental model for primary neuropathic corneal pain induced by long ciliary nerve ligation in rats.

ABSTRACT: Neuropathic corneal pain (NCP) is a new and ill-defined disease characterized by pain, discomfort, aching, burning sensation, irritation, dryness, and grittiness. However, the mechanism underlying NCP remain unclear. Here, we reported a novel rat model of primary NCP induced by long ciliary nerve (LCN) ligation. After sustained LCN ligation, the rats developed increased corneal mechanical and chemical sensitivity, spontaneous blinking, and photophobia, which were ameliorated by intraperitoneal injection of morphine or gabapentin. However, neither tear reduction nor corneal injury was observed in LCN-ligated rats. Furthermore, after LCN ligation, the rats displayed a significant reduction in corneal nerve density, as well as increased tortuosity and beading nerve ending. Long ciliary nerve ligation also notably elevated corneal responsiveness under resting or menthol-stimulated conditions. At a cellular level, we observed that LCN ligation increased calcitonin gene-related peptide (neuropeptide)-positive cells in the trigeminal ganglion (TG). At a molecular level, upregulated mRNA levels of ion channels Piezo2, TRPM8, and TRPV1, as well as inflammatory factors TNF-α, IL-1ß, and IL-6, were also detected in the TG after LCN ligation. Meanwhile, consecutive oral gabapentin attenuated LCN ligation-induced corneal hyperalgesia and increased levels of ion channels and inflammation factors in TG. This study provides a reliable primary NCP model induced by LCN ligation in rats using a simple, minimally invasive surgery technique, which may help shed light on the underlying cellular and molecular bases of NCP and aid in developing a new treatment for the disease.

Discriminative stimulus properties of two training doses of gabapentin in rats: Substitution by pregabalin, diazepam, and pentobarbital.

Gabapentin is used for the treatment of many conditions, including seizures, pain, and anxiety. Increasing reports of nonprescribed use suggest that gabapentin may elicit positive subjective effects. The present study was conducted to examine the subjective effects of gabapentin using rats trained to discriminate either a 30.0 mg/kg or 300.0 mg/kg dose of gabapentin versus vehicle on a two-choice drug discrimination task. Both doses of gabapentin were established as discriminative stimuli, and the 300.0 mg/kg dose was more readily established compared to the 30.0 mg/kg dose. Full substitution (> 80% gabapentin-lever responding) occurred by the training drug and by the gabapentinoid compound pregabalin. Partial substitution (> 20% gabapentin-lever responding) was shown by the opioid compounds morphine and fentanyl, and dose combinations of the opioid receptor antagonist naltrexone with the gabapentin training doses reduced the percentage of gabapentin-lever responding to below 80%. Partial substitution for both training doses of gabapentin occurred with the cannabinoid Δ9-tetrahydrocannabinol. The barbiturate compound pentobarbital and the benzodiazepine compound diazepam were only tested for substitution for the 300.0 mg/kg dose of gabapentin and these compounds produced full substitution. These findings demonstrate that gabapentin establishes a robust discriminative cue and exhibits stimulus effects closely similar to pregabalin, pentobarbital, and diazepam. Since pregabalin, pentobarbital, and diazepam carry a risk of problematic use and are classified as controlled substances, further evaluations of gabapentin's risks in this regard are warranted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Antinociceptive effects of fentanyl and nonopioid drugs in methocinnamox-treated rats.

BACKGROUND: A single administration of the opioid receptor antagonist methocinnamox (MCAM) antagonizes the antinociceptive effects of µ-opioid receptor agonists for 2 weeks or longer. Such a long duration of antagonism could necessitate the use of nonopioid drugs for treating pain in patients receiving MCAM for opioid use disorder (OUD). METHODS: The antinociceptive effects of fentanyl and nonopioid drugs were assessed in 24 male Sprague Dawley rats using a complete Freund's adjuvant (CFA) model of inflammatory pain. Twelve rats received 10mg/kg MCAM and 12 received vehicle; half (n=6) of the animals from each treatment group were treated (intraplantar) with CFA or saline. Hypersensitivity to mechanical stimulation was measured using a von Frey anesthesiometer. Fentanyl (0.01-0.1mg/kg), ketamine (17.8-56mg/kg), gabapentin (32-100mg/kg), meloxicam (3.2-10mg/kg), and ∆9-tetrahydrocannabinol (THC, 1-10mg/kg) were administered intraperitoneally and tested every 3 days in a pseudorandom order. Next, the same drugs were studied for effects on motor performance using a rotarod apparatus. RESULTS: CFA-induced hypersensitivity was attenuated by fentanyl in vehicle- but not MCAM-treated rats. THC, ketamine, and gabapentin attenuated (up to 82, 66, and 46 %, respectively) CFA-evoked mechanical hypersensitivity in both MCAM- and vehicle-treated rats. Meloxicam failed to alter CFA-evoked mechanical hypersensitivity in either group. Fentanyl, THC, gabapentin, and meloxicam did not affect motor performance in either group whereas ketamine impaired motor performance in both groups (up to 71 % reduction in latency to fall). CONCLUSIONS: These data suggest that ketamine, gabapentin, and THC could be effective for treating inflammatory pain under conditions of long term µ-opioid receptor antagonism.

Effect of gabapentin pretreatment on myoclonus after etomidate: a randomized, double-blind, placebo-controlled study / Efeito do pré-tratamento com gabapentina sobre a mioclonia após etomidato: um estudo randômico, duplo-cego e controlado por placebo

Abstract Aim: To evaluate the effects of three different doses of gabapentin pretreatment on the incidence and severity of myoclonic movements linked to etomidate injection. Method: One hundered patients, between 18 and 60 years of age and risk category American Society of Anesthesiologists I-II, with planned elective surgery under general anesthetic were included in the study. The patients were randomly divided into four groups and 2 h before the operation were given oral capsules of placebo (Group P, n = 25), 400 mg gabapentin (Group G400, n = 25), 800 mg gabapentin (Group G800, n = 25) or 1200 mg gabapentin (Group G1200, n = 25). Side effects before the operation were recorded. After preoxygenation for anesthesia induction 0.3 mg kg−1 etomidate was administered for 10 s. A single anesthetist with no knowledge of the study medication evaluated sedation and myoclonic movements on a scale between 0 and 3. Two minutes after induction, 2 µg kg−1 fentanyl and 0.8 mg kg−1 rocuronium were administered for tracheal intubation. Results: Demographic data were similar. Incidence and severity of myoclonus in Group G1200 and Group G800 were significantly lower than in Group P; sedation incidence and level were appreciably higher compared to Group P and Group G400. While there was no difference in the incidence of myoclonus between Group P and Group G400, the severity of myoclonus in Group G400 was lower than in the placebo group. In the two-hour period before induction other than sedation none of the side effects related to gabapentin were observed in any patient. Conclusion: Pretreatment with 800 mg and 1200 mg gabapentin 2 h before the operation increased the level of sedation and reduced the incidence and severity of myoclonic movements due to etomidate.

Resumo Objetivo: Avaliar os efeitos de três doses diferentes de gabapentina como pré-tratamento sobre a incidência e a gravidade dos movimentos mioclônicos associados à injeção de etomidato. Método: Cem pacientes, entre 18-60 anos, estado físico ASA I-II, programados para cirurgia eletiva sob anestesia geral, foram incluídos no estudo. Os pacientes foram randomicamente divididos em quatro grupos e duas horas antes da operação receberam cápsulas orais de placebo (Grupo P, n = 25), 400 mg de gabapentina (Grupo G400, n = 25), 800 mg de gabapentina (Grupo G800, n = 25) e 1.200 mg de gabapentina (Grupo G1.200, n = 25). Os efeitos colaterais antes da cirurgia foram registados. Após pré-oxigenação para a indução da anestesia, etomidate (0,3 mg.kg−1) foi administrado por 10 segundos. Um único anestesista, cego para a medicação do estudo, avaliou a sedação e os movimentos mioclônicos com uma escala de 0 a 3. Dois minutos após a indução, fentanil (2 µgr.kg−1) e rocurônio (0,8 mg.kg−1) foram administrados para a intubação traqueal. Resultados: Os dados demográficos foram semelhantes. A incidência e a gravidade da mioclonia nos grupos G1.200 e G800 foram significativamente menores do que no Grupo P; a incidência e o nível de sedação foram consideravelmente maiores comparados com o Grupo P e o Grupo G400. Enquanto não houve diferença na incidência de mioclonia entre os grupos P e G400, a gravidade da mioclonia no Grupo G400 foi menor do que no grupo placebo. No período de duas horas antes da indução, nenhum dos efeitos colaterais relacionados à gabapentina, exceto sedação, foi observado em qualquer paciente. Conclusão: O pré-tratamento com 800 mg e 1.200 mg de gabapentina duas horas antes da operação aumentou o nível de sedação e reduziu a incidência e a gravidade dos movimentos mioclônicos associados ao etomidato.

Gabapentin Differentially Modulate c-Fos Expression in Hypothalamus and Spinal Trigeminal Nucleus in Surgical Molar Extraction

Abstract The study on the efficacy of oral analgesics reported that no single class of drug is effective in post-surgical dental pain. Pain following removal of third molar is most commonly used and widely accepted acute pain model for assessing the analgesic effect of drugs in humans. Reports demonstrated that analgesic efficacy in the human dental model is highly predictive. The high incidence of false-negative findings in analgesic investigations hinders the process of molecular discovery. Molecular mechanism of post-surgical pain is not known. More importantly, the animal model for postoperative dental pain is not well established. In an attempt to discover an effective post-surgical dental pain blocker with acceptable side effects, it is essential to elucidate the molecular mechanism of post-operative dental pain. The present study investigated mandibular molars extraction in rat as an animal model for the post-operative dental pain in central nervous system. Using c-Fos immunohistochemistry, we demonstrated that pre administration of GBP (150 mg/kg. i.p) significantly (p< 0.01) neutralized the surgical molar extraction induced c-Fos expression bilaterally in rat hypothalamus. Present results indicate that pain after surgical molar extraction might follow novel neural pathways therefore difficult to treat with existing anti-nociceptive drugs.

Resumo O estudo da eficácia relativa dos analgésicos orais relatou que nenhuma classe única de fármaco é eficaz na dor pós-cirúrgica dental. A dor após a remoção do terceiro molar é o modelo de dor aguda mais comumente usado e amplamente aceito para avaliar o efeito analgésico de drogas em seres humanos. Os relatos demonstraram que a eficácia analgésica no modelo dental humano é altamente preditiva. A alta incidência de achados falso-negativos em investigações analgésicas dificulta o processo de descoberta molecular. O mecanismo molecular da dor pós-cirúrgica não é conhecido. Mais importante ainda, o modelo animal para a dor pós-operatória não está bem estabelecido. Numa tentativa de descobrir um bloqueador de dor dental pós-cirúrgico eficaz com efeitos secundários aceitáveis, é essencial elucidar o mecanismo molecular da dor pós-operatória dental. Neste estudo investigamos a extração de molares inferiores de ratos como modelo animal para a dor pós-operatória no sistema nervoso central. Utilizando análise imunohistoquímica de c-Fos, demonstrou-se que a administração prévia de GBP (150 mg/kg i.p) significativamente (p<0,01) neutralizou a expressão c-Fos induzida por extração molar cirúrgica bilateralmente no hipotálamo de rato. Os resultados indicam que a dor após a extração molar cirúrgica pode seguir novas vias neurais, portanto, difícil tratar com as drogas anti-nociceptivas existentes.

Anthropometric indicators of obesity in the prediction of high body fat in adolescents / Indicadores antropométricos de obesidade na predição de gordura corporal elevada em adolescentes

OBJECTIVE: To determine the anthropometric indicators of obesity in the prediction of high body fat in adolescents from a Brazilian State. METHODS: The study included 1,197 adolescents (15-17 years old). The following anthropometric measurements were collected: body mass (weight and height), waist circumference and skinfolds (triceps and medial calf). The anthropometric indicators analyzed were: body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR) and conicity index (C-Index). Body fat percentage, estimated by the Slaughter et al equation, was used as the reference method. Descriptive statistics, U Mann-Whitney test, and ROC curve were used for data analysis. RESULTS: Of the four anthropometric indicators studied, BMI, WHtR and WC had the largest areas under the ROC curve in relation to relative high body fat in both genders. The cutoffs for boys and girls, respectively, associated with high body fat were BMI 22.7 and 20.1kg/m², WHtR 0.43 and 0.41, WC 75.7 and 67.7cm and C-Index 1.12 and 1.06. CONCLUSIONS: Anthropometric indicators can be used in screening for identification of body fat in adolescents, because they are simple, have low cost and are non-invasive. .

OBJETIVO: Determinar os indicadores antropométricos de obesidade na predição da gordura corporal elevada em adolescentes de um estado brasileiro. MÉTODOS: O estudo incluiu 1.197 adolescentes (15-17 anos). As seguintes medidas antropométricas foram coletadas: massa corporal e estatura, perímetro da cintura e dobras cutâneas (tríceps e perna medial). Os indicadores antropométricos analisados foram: índice de massa corporal (IMC), perímetro da cintura (PC), razão cintura-estatura (RCE) e índice de conicidade (IC). A gordura corporal elevada, estimada pela equação de Slaughter et al., foi usada como método de referência. Estatística descritiva, teste U de Mann-Whitney e curva ROC foram usadas para a análise dos dados. RESULTADOS: Dos quatro indicadores antropométricos estudados, o IMC, a RCE e o PC tiveram as maiores áreas sob a curva ROC em relação à gordura corporal elevada relativa em ambos os sexos. Os pontos de corte para os rapazes e as moças, respectivamente, associados com gordura corporal elevada foram IMC 22,7 e 20,1 kg/m2, RCE 0,43 e 0,41, PC 75,7 e 67,7 cm e IC 1,12 e 1,06. CONCLUSÕES: Os indicadores antropométricos podem ser usados como ferramenta para identificação da gordura corporal em adolescentes, por serem um método simples, de baixo custo e não invasivo. .

Effect of carbamazepine and gabapentin on excitability in the trigeminal subnucleus caudalis of neonatal rats using a voltage-sensitive dye imaging technique

BACKGROUND: The antiepileptic drugs carbamazepine and gabapentin are effective in treating neuropathic pain and trigeminal neuralgia. In the present study, to analyze the effects of carbamazepine and gabapentin on neuronal excitation in the spinal trigeminal subnucleus caudalis (Sp5c) in the medulla oblongata, we recorded temporal changes in nociceptive afferent activity in the Sp5c of trigeminal nerve-attached brainstem slices of neonatal rats using a voltage-sensitive dye imaging technique. RESULTS: Electrical stimulation of the trigeminal nerve rootlet evoked changes in the fluorescence intensity of dye in the Sp5c. The optical signals were composed of two phases, a fast component with a sharp peak followed by a long-lasting component with a period of more than 500 ms. This evoked excitation was not influenced by administration of carbamazepine (10, 100 and 1,000 µM) or gabapentin (1 and 10 µM), but was increased by administration of 100 µM gabapentin. This evoked excitation was increased further in low Mg²+ (0.8 mM) conditions, and this effect of low Mg²+ concentration was antagonized by 30 µM DL-2-amino-5-phosphonopentanoic acid (AP5), a N-methyl-D-as-partate (NMDA) receptor blocker. The increased excitation in low Mg²+ conditions was also antagonized by carbamazepine (1,000 µM) and gabapentin (100 µM). CONCLUSION: Carbamazepine and gabapentin did not decrease electrically evoked excitation in the Sp5c in control conditions. Further excitation in low Mg²+ conditions was antagonized by the NMDA receptor blocker AP5. Carbamazepine and gabapentin had similar effects to AP5 on evoked excitation in the Sp5c in low Mg²+ conditions. Thus, we concluded that carbamazepine and gabapentin may act by blocking NMDA receptors in the Sp5c, which contributes to its anti-hypersensitivity in neuropathic pain.