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Due to the high incidence and severity of obesity and its related disorders, it is highly desirable to develop new strategies to treat or even to prevent its development. We have previously described that Ginkgo biloba extract (GbE) improved insulin resistance and reduced body weight gain of obese rats. In the present study we aimed to evaluate the effect of GbE on both inflammatory cascade and insulin signaling in retroperitoneal fat depot of diet-induced obese rats. Rats were fed with high fat diet for 2 months and thereafter treated for 14 days with 500 mg/kg of GbE. Rats were then euthanized and samples from retroperitoneal fat depot were used for western blotting, RT-PCR, and ELISA experiments. The GbE treatment promoted a significant reduction on both food/energy intake and body weight gain in comparison to the nontreated obese rats. In addition, a significant increase of both Adipo R1 and IL-10 gene expressions and IR and Akt phosphorylation was also observed, while NF-κB p65 phosphorylation and TNF-α levels were significantly reduced. Our data suggest that GbE might have potential as a therapy to treat obesity-related metabolic diseases, with special interest to treat obese subjects resistant to adhere to a nutritional education program.
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Ginkgo biloba/química , Inflamação/tratamento farmacológico , Insulina/metabolismo , Gordura Intra-Abdominal/patologia , Obesidade/tratamento farmacológico , Extratos Vegetais/química , Animais , Peso Corporal , Dietoterapia , Modelos Animais de Doenças , Ingestão de Energia , Resistência à Insulina , Gordura Intra-Abdominal/efeitos dos fármacos , Masculino , Fosforilação , Fitoterapia , Ratos , Ratos Wistar , Transdução de SinaisRESUMO
Depression will be the disease with the highest incidence worldwide by 2030. Data indicate that postmenopausal women have a higher incidence of mood disorders, and this high vulnerability seems to be related to hormonal changes and weight gain. Although research evaluating the profile of metabolites in mood disorders is advancing, further research, maintaining consistent methodology, is necessary to reach a consensus. Therefore, the objective of the present study was to carry out an exploratory analysis of the plasma polar metabolites of pre- and postmenopausal women to explore whether the profile is affected by depression. The plasma analysis of 50 polar metabolites was carried out in a total of 67 postmenopausal women, aged between 50 and 65 years, either without depression (n = 25) or with depression symptoms (n = 42), which had spontaneous onset of menopause and were not in use of hormone replacement therapy, insulin, or antidepressants; and in 42 healthy premenopausal women (21 without depression and 21 with depression symptoms), aged between 40 and 50 years and who were not in use of contraceptives, insulin, or antidepressants. Ten metabolites were significantly affected by depression symptoms postmenopause, including adenosine (FDR = 3.778 × 10-14), guanosine (FDR = 3.001 × 10-14), proline (FDR = 1.430 × 10-6), citrulline (FDR = 0.0001), lysine (FDR = 0.0004), and carnitine (FDR = 0.0331), which were down-regulated, and dimethylglycine (FDR = 0.0022), glutathione (FDR = 0.0048), creatine (FDR = 0.0286), and methionine (FDR = 0.0484) that were up-regulated. In premenopausal women with depression, oxidized glutathione (FDR = 0.0137) was down-regulated, and dimethylglycine (FDR = 0.0406) and 4-hydroxyproline (FDR = 0.0433) were up-regulated. The present study provided new data concerning the consequences of depression on plasma polar metabolites before and after the establishment of menopause. The results demonstrated that the postmenopausal condition presented more alterations than the premenopausal period and may indicate future measures to treat the disturbances involved in both menopause and depression.
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Our previous behavioral and molecular data indicate a central role of the dorsal hippocampal formation (dHF) in recent conditioned lick suppression memory. The purpose of this study was to investigate the role of the dHF in recent and remote memory of conditioned lick suppression employing proteomic analysis. Two or 40 days after conditioning, the rats were subjected to a retention test and were then euthanized after 24 hr for dHF collection. We identified 1,165 proteins and quantified 265 proteins. Upregulation of five proteins and downregulation of 21 proteins were found on postconditioning Day 2. Additionally, four proteins were upregulated and 21 proteins were downregulated on postconditioning Day 40. Integrated pathway analysis of the proteomics data indicated changes in the myelin sheath, neuron generation and differentiation, regulation of neurogenesis and synaptic vesicle transport, axonal development, and the growth cone. Our findings provide further support for the role of the dHF in conditioned lick suppression memory and novel insights into the molecular changes that are correlated with recent and remote memory in the dHF, which may be a target for cognitive enhancers. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Proteoma , Proteômica , Ratos , Animais , Proteoma/metabolismo , Hipocampo/metabolismo , Memória , Medo/fisiologiaRESUMO
Bioactive metabolites from Bauhinia forficata Link (Bf extract) hold therapeutic potential for type 2 diabetes mellitus (T2DM) but the mechanism remains poorly understood. This study aimed to test the extract from Bf leaves obtained by decoction on the prevention of T2DM in vivo. The Bf extract was tested on a streptozotocin-induced T2DM mouse model fed on a high-fat diet. The insulin resistance was attenuated in T2DM animals supplemented with Bf extract, which indicates glucose intolerance reduction and p-AKT/AKT ratio preservation in the gastrocnemius muscle. These observations suggested that Bf extract enhanced glucose uptake. Nevertheless, there was no preservation in ß-cell insulin secretion in Bf extract-treated T2DM mice. Interestingly, the Bf extract reduced body weight gain without affecting total energy intake. Hence, Bf extract has a hypoglycemic effect which could attenuate the development of insulin resistance.
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Bauhinia , Diabetes Mellitus Tipo 2 , Resistência à Insulina , Camundongos , Animais , Diabetes Mellitus Tipo 2/tratamento farmacológico , Proteínas Proto-Oncogênicas c-akt , Hipoglicemiantes , Glucose , Músculo Esquelético/metabolismo , Insulina , Glicemia/metabolismoRESUMO
Introduction: Thyroid hormones exert multiple physiological effects essential to the maintenance of basal metabolic rate (BMR), adaptive thermogenesis, fat metabolism, growth, and appetite. The links between obesity and the hormones of the thyroid axis, i.e., triiodothyronine (T3), thyroxine (T4), and thyrotropin (TSH), are still controversial, especially when considering children and adolescents. This population has high rates of overweight and obesity and several treatment approaches, including nutritional, psychological, and physical exercise interventions have been used. Understanding the importance of the hormones of the thyroid axis in the recovery from overweight and obesity may help directing measures to the maintenance of a healthy body composition. The present scoping review was carried out to analyze studies evaluating these hormonal levels throughout interventions directed at treating overweight and obesity in children and adolescents. The main purpose was to ascertain whether the hormones levels vary during weight loss. Methods: We selected for analysis 19 studies published between 1999 and 2022. Results: Most of the studies showed that changes in different anthropometric indicators, in response to the multidisciplinary interventions, correlated positively with free T3 (fT3), total T3 (TT3), and TSH. With respect to free T4 (fT4) and total T4 (TT4). Discussion: The most common finding was of unchanged levels and, hence, no significant association with weight loss. Moreover, thyroxine supplementation has failed to affect the response to the interventions. Further studies are necessary to elucidate the relevance of the variations in hormone levels to the establishment of overweight/obesity and to the recovery from these conditions in children/adolescents. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42020203359.
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Smaller adipocytes are related to the reversal of metabolic disorders, suggesting that molecules that can act in the adipogenesis pathway are of great interest. The objective of this study was to investigate the effect of Ginkgo biloba extract (GbE) in modulating the differentiation in preadipocytes. 3T3-L1 preadipocytes were differentiated for 7 days into adipocytes without (control group) and with GbE at 1.0 mg/mL. Lipid content and gene expression were analyzed on day 7 (D7) by Oil Red O staining and PCR Array Gene Expression. Western blotting analysis of the key adipogenesis markers was evaluated during the differentiation process at days 3 (D3), 5 (D5), and 7 (D7). GbE increased lipid content and raised the gene expression of the main adipogenesis markers. Key proteins of the differentiation process were modulated by GbE, since C/EBPß levels were decreased, while C/EBPα levels were increased at D7. Regarding the mature adipocytes' markers, GbE enhanced the levels of both FABP4 at D5, and perilipin at D3 and D5. In summary, the present findings showed that GbE modulated the adipogenesis pathway suggesting that the treatment could accelerate the preadipocyte maturation, stimulating the expression of mature adipocyte proteins earlier than expected.
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Menopause may be accompanied by abdominal obesity and inflammation, conditions accentuated by high-fat intake, especially of saturated fat (SFA)-rich diets. We investigated the consequences of high-SFA intake on the fatty acid (FA) profile of monoglycerides, diglycerides and cholesteryl esters from retroperitoneal white adipose tissue (RET) of rats with ovariectomy-induced menopause, and the effect of oestradiol replacement. Wistar rats were either ovariectomized (Ovx) or sham operated (Sham) and fed either standard chow (C) or lard-enriched diet (L) for 12 weeks. Half of the Ovx rats received 17ß-oestradiol replacement (Ovx + E2). Body weight and food intake were measured weekly. RET neutral lipids were chromatographically separated and FAs analysed by gas chromatography. Ovariectomy alone increased body weight, feed efficiency, RET mass, leptin and insulin levels, leptin/adiponectin ratio, HOMA-IR and HOMA-ß indexes. OvxC + E2 showed attenuation in nearly all blood markers. HOMA-ß index was restored in OvxL + E2. OvxC showed significantly disturbed SFA and polyunsaturated FA (PUFA) profile in RET cholesteryl esters (CE). OvxC also showed increased monounsaturated FA (MUFA) in the monoglyceride diglyceride (Mono-Di) fraction. Similar changes were not observed in OvxL, although increased SFA and decreased PUFA was observed in Mono-Di. Overall, HRT was only partially able to revert changes induced by ovariectomy. There appears to be increased mobilization of essential FA in Ovx via CE, which is a dynamic lipid species. The same results were not found in Mono-Di, which are more inert. HRT may be helpful to preserve FA profile in visceral fat, but possibly not wholly sufficient in reverting the metabolic effects induced by menopause.
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Tecido Adiposo/metabolismo , Ésteres do Colesterol/metabolismo , Diglicerídeos/metabolismo , Terapia de Reposição de Estrogênios , Monoglicerídeos/metabolismo , Ovariectomia , Tecido Adiposo/efeitos dos fármacos , Animais , Biomarcadores , Peso Corporal , Dieta Hiperlipídica , Feminino , Metabolismo dos Lipídeos/efeitos dos fármacos , Ovariectomia/efeitos adversos , RatosRESUMO
We have previously shown increased depression and anxiety scores in postmenopausal overweight women, when compared to overweight premenopausal women. The mechanisms responsible for these alterations are not understood. Although ghrelin involvement in mood modulation has been suggested, its role is still ambiguous and has not been evaluated in postmenopause. Here we investigated the association of ghrelin with depression and anxiety symptoms in postmenopausal women. Fifty-five postmenopausal women with depression symptoms, who were not in use of hormones or antidepressants, were included in the study. Depression symptoms were evaluated by Beck's Depression Inventory (BDI) and Patient Health Questionnaire-9 (PHQ-9) and anxiety symptoms were evaluated by Beck's Anxiety Inventory (BAI). Women were allocated into three groups, according to BDI classification of mild, moderate, or severe depression symptoms. Anthropometric, biochemical and hormonal parameters were analyzed. Total and acylated ghrelin levels were higher in the severe depression than in the mild depression group. Multivariate regression analyses showed positive associations of BDI scores with acylated ghrelin and BMI, and of PHQ-9 scores with acylated ghrelin and homeostasis model assessment of insulin resistance (HOMA-IR). BAI scores associated positively with waist-to-hip ratio. To the best of our knowledge, this is the first demonstration of an association between acylated ghrelin and the severity of depression symptoms in postmenopausal women. This association may reflect either a physiological response aimed at fighting against depression symptoms or a causal factor of this mental disorder.
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Ansiedade/diagnóstico , Depressão/metabolismo , Grelina/metabolismo , Sobrepeso , Pós-Menopausa , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Sobrepeso/metabolismo , Sobrepeso/psicologia , Pós-Menopausa/metabolismo , Pós-Menopausa/psicologiaRESUMO
Since Ginkgo biloba extract (GbE) was reported to improve the hypothalamic serotonergic system of ovariectomized (OVX) rats, the present study aimed to verify the GbE effects on hippocampal oxidative stress, inflammation, and levels of the serotonin transporter (5-HTT), and both the serotonin (5-HT1A, 5-HT1B) and leptin receptors of OVX rats. Two-month-old female Wistar rats had their ovaries surgically removed (OVX) or not (SHAM). After 60 days, OVX rats were gavaged daily with GbE 500 mg kg-1 (OVX+GbE), while SHAM and OVX groups received saline 0.9% (vehicle) for 14 days. Rats were then euthanized, and hippocampi were collected. Both 5-HT1A and 5-HT1B levels were significantly reduced in OVX rats compared to SHAM rats, while 5-HT1A was higher in OVX+GbE rats in comparison to OVX rats. Similarly, LepR levels were increased in OVX+GbE rats compared to OVX rats, reaching similar levels to SHAM rats. Superoxide dismutase activity increased in OVX rats in relation to SHAM rats, which was restored to SHAM levels by GbE treatment. Additionally, GbE significantly increased the glutathione peroxidase activity in comparison to the SHAM group. No differences were observed either in catalase activity or in the levels of 5-HTT, PKCα, TLR-4, NF-κBp50, ERK, and CREB. In summary, our results show a potential effect of GbE on hippocampal pathways involved in feeding behavior, and thus, they suggest that GbE activity might improve menopausal-related hippocampal disorders, offering an alternative therapeutic tool particularly for women to whom hormone replacement therapy may be contraindicated.
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Antioxidantes/farmacologia , Hipocampo/metabolismo , Ovariectomia , Extratos Vegetais/farmacologia , Receptores para Leptina/metabolismo , Receptores de Serotonina/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Feminino , Flavonoides/análise , Ginkgo biloba , Inflamação/patologia , Ratos Wistar , Serotonina/metabolismo , Terpenos/análiseRESUMO
While several pieces of evidence link obesity and mood disorders in menopause, the mechanisms involved are not yet fully understood. We have previously demonstrated that Ginkgo biloba extract (GbE) both attenuated diet-induced obesity of male rats and restored serotonin-induced hypophagia in ovariectomized female rats. The present study aimed at exploring whether GbE treatment ameliorates ovariectomy-related obesity and anxious/depressive-like behaviours. Wistar female rats were either ovariectomized (OVX) or sham-operated (Sham). After 2 months, either 500 mg/kg of GbE or vehicle were administered daily by gavage for 14 days. Anxious/depressive-like behaviours were assessed by the Elevated Plus Maze and the Forced Swim Tests, respectively. Ovariectomy caused high visceral adiposity, hyperleptinemia, and hypercholesterolemia, and increased the anxiety index (p = 0.048 vs. Sham + GbE) while it decreased the latency to immobility (p = 0.004 vs. Sham). GbE treatment in OVX rats improved body composition, adiponectin levels and blood lipid profile. It also reduced the anxiety index (p = 0.004) and increased the latency to immobility (p = 0.003) of OVX rats. Linear regression analysis demonstrated that leptin (p = 0.047) and total cholesterol levels (p = 0.022) were associated with anxious-like behaviours while body adiposity (p = 0.00005) was strongly associated with depressive-like behaviours. The results showed that GbE therapy was effective in attenuating the deleterious effects of ovariectomy on body composition, lipid profile, and anxious/depressive-like behaviours. Further studies are warranted to better understand the therapeutic potential of GbE in menopause.
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Ansiedade/tratamento farmacológico , Depressão/tratamento farmacológico , Obesidade/tratamento farmacológico , Ovariectomia/efeitos adversos , Extratos Vegetais/farmacologia , Animais , Ansiedade/etiologia , Depressão/etiologia , Teste de Labirinto em Cruz Elevado , Feminino , Ginkgo biloba , Ovariectomia/psicologia , Extratos Vegetais/uso terapêutico , Ratos , Ratos WistarRESUMO
We have previously shown that standardized extracts of Ginkgo biloba (EGb) modulate fear memory formation, which is associated with CREB-1 (mRNA and protein) upregulation in the dorsal hippocampal formation (dHF), in a dose-dependent manner. Here, we employed proteomic analysis to investigate EGb effects on different protein expression patterns in the dHF, which might be involved in the regulation of CREB activity and the synaptic plasticity required for long-term memory (LTM) formation. Adult male Wistar rats were randomly assigned to four groups (n = 6/group) and were submitted to conditioned lick suppression 30 min after vehicle (12% Tween 80) or EGb (0.25, 0.50, and 1.00 gâ kg-1) administration (p.o). All rats underwent a retention test session 48 h after conditioning. Twenty-four hours after the test session, the rats were euthanized via decapitation, and dHF samples were removed for proteome analysis using two-dimensional polyacrylamide gel electrophoresis, followed by peptide mass fingerprinting. In agreement with our previous data, no differences in the suppression ratios (SRs) were identified among the groups during first trial of CS (conditioned stimulus) presentation (P > 0.05). Acute treatment with 0.25 gâ kg-1 EGb significantly resulted in retention of original memory, without prevent acquisition of extinction within-session. In addition, our results showed, for the first time, that 32 proteins were affected in the dHF following treatment with 0.25, 0.50, and 1.00 gâ kg-1 doses of EGb, which upregulated seven, 19, and five proteins, respectively. Additionally, EGb downregulated two proteins at each dose. These proteins are correlated with remodeling of the cytoskeleton; the stability, size, and shape of dendritic spines; myelin sheath formation; and composition proteins of structures found in the membrane of the somatodendritic and axonal compartments. Our findings suggested that EGb modulates conditioned suppression LTM through differential protein expression profiles, which may be a target for cognitive enhancers and for the prevention or treatment of neurocognitive impairments.
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Serotonin-induced anorexia has long been recognized as an important part of the CNS mechanisms controlling energy balance. More recently, interleukin-1beta and nitric oxide have been suggested to influence this control, possibly through modulation of hypothalamic serotonin. The present work aimed at investigating the interaction of these systems. We addressed whether 5-HT is affected during IL-1beta-induced anorexia in obese Zucker rats and the influence of the central NO system on this IL-1beta/5-HT interaction. Using microdialysis, we observed that an intracerebroventricular injection of 10 ng IL-1beta significantly stimulated 5-HT extracellular levels in the VMH, with a peak variation of 102+/-41% above baseline. IL-1beta also significantly reduced the 4-h feeding by 33% and the 24-h feeding by 42%. Contrarily, these effects were absent when IL-1beta was injected 2 h after the i.c.v. administration of 20 microg of the NO precursor L-arginine. The results suggest that, in obese Zucker rats, activation of the serotonergic system in the medial hypothalamus participates in IL-1beta-induced anorexia. Since L-arginine, probably through NO stimulation, abolished both the anorexia and the serotonergic activation, it can be proposed that the NO system, either directly or indirectly, counteracts IL-1beta anorexia. The hypothalamic serotonergic system is likely to mediate this NO effect.
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Comportamento Alimentar/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Interleucina-1/farmacologia , Óxido Nítrico/metabolismo , Obesidade/metabolismo , Serotonina/metabolismo , Animais , Ingestão de Alimentos/efeitos dos fármacos , Ácido Hidroxi-Indolacético/metabolismo , Microdiálise , Ratos , Ratos ZuckerRESUMO
Both hypothalamic serotonin and leptin reduce energy intake and stimulate expenditure. There are evidence that increased serotonin metabolism may be involved in leptin actions. Using microdialysis, we directly assessed the effect of an intracerebroventricular leptin injection on 5-HT release in the lateral hypothalamus of normal rats. When LH microdialysates were collected in the absence of food intake, neither artificial cerebrospinal fluid (CSF) nor 10 microg leptin i.c.v. caused significant variations in 5-HT release, measured for 2 h post-injection, at 20-min periods. When food was ingested after CSF, 5-HT release increased significantly, with a maximal elevation of 51+/-16% above baseline occurring at the 100-120 min post-injection interval. Leptin inhibited food intake (-75% at 0-20 min and -73% at 20-40 min) while it accentuated the food-induced serotonergic activation. At the 0-20 min interval, serotonin release was significantly higher after leptin (42+/-12% above baseline) than after CSF (6+/-5%) and the maximal increase after leptin was of 126+/-53% above baseline (100-120 min, p>0.05 vs. CSF). These observations indicate that leptin probably interacts with the serotonergic-stimulating mechanisms elicited by food intake, intensifying them. The additional serotonergic activation induced by leptin may be significant for the hormone effects on energy balance.
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Leptina/farmacologia , Serotonina/farmacologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Encéfalo/metabolismo , Líquido Cefalorraquidiano/metabolismo , Cromatografia Líquida de Alta Pressão , Ingestão de Alimentos , Leptina/metabolismo , Masculino , Obesidade , Ratos , Ratos Wistar , Serotonina/metabolismo , Fatores de TempoRESUMO
BACKGROUND: Obesity is associated with increased adipose tissue and glucose intolerance. High-fat diets (HFDs) are known to induce obesity and increase proinflammatory adipokines. The consumption of green tea may improve the health of obese individuals because it contains a potent antioxidant that has effects on body weight, energy expenditure and serum cholesterol concentrations. METHODS: We examined the effects of epigallocatechin-3-gallate (EGCG) (50 mg/kg body weight per day) or saline after 30 or 60 days of treatment. Mice were distributed into four groups: 1) NS: normolipidic diet receiving saline; 2) NE: normolipidic diet receiving EGCG; 3) HFS: high-fat diet receiving saline; 4) HFE: high-fat diet receiving EGCG. RESULTS: We observed that administration of a HFD plus EGCG treatment for 60 days reduced delta weight, the relative weights of the mesenteric adipose tissue (MES), retroperitonial adipose tissue (RET), epididymal adipose tissue (EPI), the sum of the adipose tissues (SAT), reduced triacylglycerol (TG) and improved both high-density lipoprotein (HDL) cholesterol levels and the adiponectin/STA ratio when compared with HFS. CONCLUSIONS: Our results suggest that the chronic administration of EGCG (60 days) promoted a significant improvement in glucose tolerance, decreased adipose tissue deposits, weight mass, TG and HDL-C only when associated with high-fat diet treatment.
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Whether leptin targets the hypothalamic serotonergic system to inhibit food intake is not established. We examined the effect of a short-term i.c.v. leptin treatment on serotonin microdialysate levels in rat lateral hypothalamus. Adipose tissue gene expression was also evaluated. Male rats received four daily injections of leptin (5 µg) or vehicle (with pair-feeding to leptin-induced intake) and a fifth injection during collection of LH microdialysates. We found that serotonin and 5-HIAA levels were not affected by the leptin pre-treatment, as basal levels were similar between the leptin and the pair-fed group. These levels remained unaltered after the acute leptin injection. For gene expression studies, rats were pre-treated with five daily injections of either leptin (5 µg) or vehicle (with either pair-feeding or ad libitum intake). mRNA levels of resistin, adiponectin, lipoprotein lipase, and PPAR-gamma were unaltered by either leptin or pair-feeding. Leptin gene expression was significantly reduced by leptin but not by pair-feeding, in both the retroperitoneal (-74%) and the epididymal (-99%) depots while no differences were observed in the subcutaneous depot. The observations confirmed the absence of an acute stimulatory effect of central leptin on serotonin release in the lateral hypothalamus and showed that the pre-treatment with leptin failed to modify this pattern. This indicates that components of the serotonergic system are probably not directly affected by leptin. Additionally, the central effect of leptin was able to downregulate its own adipose tissue gene expression in a depot-specific manner while other adipokine genes were not affected.
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Ingestão de Alimentos/efeitos dos fármacos , Hipotálamo/metabolismo , Leptina/farmacologia , Serotonina/metabolismo , Tecido Adiposo/metabolismo , Animais , Ingestão de Alimentos/genética , Expressão Gênica , Ácido Hidroxi-Indolacético/metabolismo , Hipotálamo/efeitos dos fármacos , Leptina/genética , Leptina/metabolismo , Masculino , Microdiálise , RNA Mensageiro/metabolismo , Ratos , Resistina/genética , Resistina/metabolismoRESUMO
O hormônio adipocitário leptina exerce um papel fundamental na manutenção da homeostase energética, promovendo redução tanto da ingestão alimentar como da massa corporal. Diversos estudos indicam que o efeito anorexígeno da leptina decorre de sua ação sobre circuitos centrais envolvidos no controle do balanço energético. Entretanto, os mecanismos pelos quais a leptina exerce suas ações centrais ainda não se encontram totalmente elucidados. O presente estudo teve como um de seus objetivos avaliar se a leptina exerce seu efeito anorexígeno via ativação do sistema serotonérgico. Ratos Wistar normais foram tratados com 4 injeções i.c.v. diárias de 5μg ou lOμg de leptina (grupos Lep5 e LeplO) ou pré-tratados com veículo e acesso à alimentação pareada aos respectivos grupos tratados (PF5 e PF10). No quinto dia, os animais permaneceram em jejum e amostras de dialisato foram coletadas do hipotálamo lateral. Durante o experimento de microdiálise, todos os grupos receberam uma injeção aguda de veículo seguida, uma hora depois, de uma injeção aguda de leptina. o pré-tratamento com leptina i.c.v. promoveu redução significante da ingestão alimentar. Observamos que esta redução ocorreu de forma dose-dependente, já que em relação ao grupo Lep5, o grupo Lep10 apresentou redução significante do consumo alimentar nos dias 3 e 4 de pré-tratamento. Os níveis basais de serotonina (5-HT) hipotalâmica foram semelhantes entre os grupos, ao passo que os níveis de ácido 5-hidroxindolacético (5-HIAA) foram mais baixos nos grupos PF10 e Lep10. Tanto no grupo PF5 como no Lep5, os níveis de 5-HT permaneceram estáveis após a injeção de veículo ou leptina, enquanto os níveis de 5¬HIAA aumentaram, indicando um aumento da síntese de 5-HT. Os grupos PF10 e Lep 10 apresentaram respostas diferentes ao tratamento. No grupo PF10, os níveis de 5-HT caíram logo após a injeção do veículo sendo que a dose aguda de leptina não modificou este efeito. Por outro lado, as injeções agudas tanto de...