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1.
Behav Brain Res ; 452: 114544, 2023 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-37321312

RESUMO

Behavioral studies are commonly used as a standard procedure to evaluate anxiety and depression in animal models. Recently, different methods have been developed to improve data collection and analysis of the behavioral tests. Currently available methods, including manual analysis and commercially available products, are either time-consuming or costly. The objective of this study was to improve the collection and analysis of behavioral test data in animal models by developing an image processing program. Eleven behavioral parameters were evaluated by three different methods, including (i) manual detection, (ii) commercially available TopScan software (CleverSys Inc, USA), and (iii) In-housed-developed Advanced Move Tracker (AMT) software. Results obtained from different methods were compared to validate the accuracy and efficiency of AMT. Results showed that AMT software provides highly accurate and reliable data analysis compared to other methods. Less than 5% tolerance was reported between results obtained from AMT compared to TopScan. In addition, the analysis processing time was remarkably reduced (68.3%) by using AMT compared to manual detection. Overall, the findings confirmed that AMT is an efficient program for automated data analysis, significantly enhancing research outcomes through accurate analysis of behavioral test data in animal models.


Assuntos
Escala de Avaliação Comportamental , Software , Animais , Processamento de Imagem Assistida por Computador/métodos , Coleta de Dados , Modelos Animais
2.
Int J Mol Sci ; 23(19)2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36232524

RESUMO

Methamphetamine (METH) is a highly addictive drug abused by millions of users worldwide, thus becoming a global health concern with limited management options. The inefficiency of existing treatment methods has driven research into understanding the mechanisms underlying METH-induced disorders and finding effective treatments. This study aims to understand the complex interactions of the gastrointestinal-immune-nervous systems following an acute METH dose administration as one of the potential underlying molecular mechanisms concentrating on the impact of METH abuse on gut permeability. Findings showed a decreased expression of tight junction proteins ZO-1 and EpCAm in intestinal tissue and the presence of FABP-1 in sera of METH treated mice suggests intestinal wall disruption. The increased presence of CD45+ immune cells in the intestinal wall further confirms gut wall inflammation/disruption. In the brain, the expression of inflammatory markers Ccl2, Cxcl1, IL-1ß, TMEM119, and the presence of albumin were higher in METH mice compared to shams, suggesting METH-induced blood-brain barrier disruption. In the spleen, cellular and gene changes are also noted. In addition, mice treated with an acute dose of METH showed anxious behavior in dark and light, open field, and elevated maze tests compared to sham controls. The findings on METH-induced inflammation and anxiety may provide opportunities to develop effective treatments for METH addiction in the future.


Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Estimulantes do Sistema Nervoso Central , Metanfetamina , Albuminas/metabolismo , Transtornos Relacionados ao Uso de Anfetaminas/metabolismo , Animais , Ansiedade , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Estimulantes do Sistema Nervoso Central/farmacologia , Molécula de Adesão da Célula Epitelial/metabolismo , Inflamação/metabolismo , Metanfetamina/metabolismo , Metanfetamina/toxicidade , Camundongos
3.
Adv Physiol Educ ; 43(2): 233-240, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31088160

RESUMO

Bioscience is a foundational unit (subject) of undergraduate allied health degree programs, providing students the scientific basis underpinning their clinical practice. However, despite its significance, bioscience is a difficult academic hurdle for many students to master. The introduction of active learning strategies, including small team-based guided-inquiry learning approaches, has been shown to significantly reduce this hurdle and improve assessment outcomes for the learner. Guided team-based activities can aid in this approach by also building broader skills and capabilities, like teamwork and communication, as well as subject-specific knowledge and skills, thereby positively influencing student assessment outcomes. This paper details the redesign and evaluation of two first-year Bioscience for Paramedics units with the introduction of guided-inquiry learning, as well as other active learning strategies, and assesses their impact on student performance. Results indicate that active learning used within a classroom and in the large lecture theater setting improved students' grades with positive student perception of their learning experience.


Assuntos
Desempenho Acadêmico , Pessoal Técnico de Saúde/educação , Ocupações em Saúde/educação , Aprendizagem Baseada em Problemas/métodos , Estudantes de Ciências da Saúde , Humanos
4.
Brain Behav ; 8(12): e01102, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30353709

RESUMO

INTRODUCTION: In Prader-Willi syndrome (PWS), nonprotein coding small nucleolar (sno) RNAs are involved in the paternally deleted region of chromosome 15q11.2-q13, which is believed to cause the hyperphagic phenotype of PWS. Central to this is SnoRNA116. The supplement Caralluma fimbriata extract (CFE) has been shown to decrease appetite behavior in some individuals with PWS. We therefore investigated the mechanism underpinning the effect of CFE on food intake in the Snord116del mouse. Experiments utilized appetite stimulants which included a 5-hydroxytryptamine (5-HT) 2c receptor antagonist (SB242084), as the 5-HT2cR is implicated in central signaling of satiety. METHODS: After 9-week chronic CFE treatment (33 mg or 100 mg kg-1  day-1 ) or placebo, the 14-week-old Snord116del (SNO) and wild-type mice (n = 72) were rotated through intraperitoneal injections of (a) isotonic saline; (b) 400 mg/kg of 2-deoxyglucose (2DG) (glucose deprivation); (c) 100 mglkg beta-mercaptoacetate (MA), fatty acid signaling; and (d) SB242084 (a selective 5HT2cR antagonist), with 5 days between reagents. Assessments of food intake were from baseline to 4 hr, followed by immunohistochemistry of neural activity utilizing c-Fos, neuropeptide Y, and alpha-melanocyte-stimulating hormone within hypothalamic appetite pathways. RESULTS: Caralluma fimbriata extract administration decreased food intake more strongly in the SNO100CFE group with significantly stimulated food intake demonstrated during coadministration with SB242084. Though stimulatory deprivation was expected to stimulate food intake, 2DG and MA resulted in lower intake in the snord116del mice compared to the WT animals (p = <0.001). Immunohistochemical mapping of hypothalamic neural activity was consistent with the behavioral studies. CONCLUSIONS: This study identifies a role for the 5-HT2cR in CFE-induced appetite suppression and significant stimulatory feeding disruptions in the snord116del mouse model.


Assuntos
Apocynaceae , Extratos Vegetais/farmacologia , Síndrome de Prader-Willi/tratamento farmacológico , Receptor 5-HT2C de Serotonina/efeitos dos fármacos , Aminopiridinas/farmacologia , Animais , Depressores do Apetite/farmacologia , Deleção Cromossômica , Modelos Animais de Doenças , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Deleção de Genes , Humanos , Hipotálamo/metabolismo , Indóis/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Fenótipo , Fitoterapia , RNA Nucleolar Pequeno/genética , Distribuição Aleatória , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia
5.
J Mol Endocrinol ; 58(4): 193-198, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28356324

RESUMO

Insulin-regulated aminopeptidase (IRAP) co-localizes with the glucose transporter 4 (GLUT4) in GLUT4 storage vesicles (GSV) in insulin-responsive cells. In response to insulin, IRAP is the only transmembrane enzyme known to translocate together with GLUT4 to the plasma membrane in adipocytes and muscle cells. Although the intracellular region of IRAP is associated with GLUT4 vesicle trafficking, the role of the aminopeptidase activity in insulin-responsive cells has not been elucidated. The aim of this study was to investigate whether the inhibition of the aminopeptidase activity of IRAP facilitates glucose uptake in insulin-responsive cells. In both in vitro and in vivo studies, inhibition of IRAP aminopeptidase activity with the specific inhibitor, HFI-419, did not modulate glucose uptake. IRAP inhibition in the L6GLUT4myc cell line did not alter glucose uptake in both basal and insulin-stimulated state. In keeping with these results, HFI419 did not affect peripheral, whole-body glucose handling after an oral glucose challenge, neither in normal rats nor in the streptozotocin (STZ)-induced experimental rat model of diabetes mellitus (DM). Therefore, acute inhibition of IRAP aminopeptidase activity does not affect glucose homeostasis.


Assuntos
Cistinil Aminopeptidase/genética , Diabetes Mellitus Experimental/enzimologia , Transportador de Glucose Tipo 4/genética , Glucose/metabolismo , Insulina/farmacologia , Animais , Transporte Biológico , Diferenciação Celular , Linhagem Celular , Cistinil Aminopeptidase/antagonistas & inibidores , Cistinil Aminopeptidase/metabolismo , Desoxiglucose/farmacologia , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Regulação da Expressão Gênica , Transportador de Glucose Tipo 4/metabolismo , Insulina/metabolismo , Masculino , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Inibidores de Proteases/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais , Estreptozocina
6.
Neurosci Biobehav Rev ; 59: 155-72, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26475993

RESUMO

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder resulting from a deletion in the expression of the paternally derived alleles in the region of 15q11-q13. PWS has a prevalence rate of 1:10,000-1:30,000 and is characterized by marked endocrine abnormalities including growth hormone deficiency and raised ghrelin levels. The hyperphagic phenotype in PWS is established over a number of phases and is exacerbated by impaired satiety, low energy expenditure and intellectual difficulties including obsessive-compulsive disorder and/or autistic behaviours. Clinical management in PWS typically includes familial/carer restriction and close supervision of food intake. If the supervision of food is left unmanaged, morbid obesity eventuates, central to the risk of cardiorespiratory disorder. None of the current appetite management/intervention strategies for PWS include pharmacological treatment, though recent research shows some promise. We review the established aberrant genetics and the endocrine and neuronal attributes which may determine disturbed regulatory processes in PWS. Focusing on clinical trials for appetite behaviours in PWS, we define the effectiveness of pharmacological treatments with a view to initiating and focusing research towards possible targets for modulating appetite in PWS.


Assuntos
Apetite/fisiologia , Comportamento/fisiologia , Ingestão de Alimentos/fisiologia , Transtorno Obsessivo-Compulsivo/genética , Síndrome de Prader-Willi/tratamento farmacológico , Síndrome de Prader-Willi/metabolismo , Animais , Humanos , Hiperfagia/metabolismo
7.
Pharmacol Res ; 84: 1-11, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24754973

RESUMO

The mechanism of action of the combination therapy, naltrexone/bupropion (NB), for obesity has not been fully described to date. Weight loss attempts rarely result in long-term success. This is likely a result of complex interactions among multiple peripheral and CNS systems that defend against weight loss, and may explain the overwhelming lack of effective obesity treatments. NB is an investigational combination therapy for obesity that was developed based on evidence that obesity involves alterations in the hypothalamic melanocortin system as well as brain reward systems that influence food craving and mood. Naltrexone and bupropion both have actions in these brain regions that may cause them to influence food intake, food craving, and other aspects of eating behavior that affect body weight. We review the individual actions of naltrexone and bupropion in brain hypothalamic and reward systems, and describe the current in vitro, in vivo, and clinical evidence for how NB influences food intake and produces weight loss.


Assuntos
Antidepressivos de Segunda Geração/uso terapêutico , Bupropiona/uso terapêutico , Naltrexona/uso terapêutico , Antagonistas de Entorpecentes/uso terapêutico , Obesidade/tratamento farmacológico , Redução de Peso/efeitos dos fármacos , Antidepressivos de Segunda Geração/farmacologia , Bupropiona/farmacologia , Quimioterapia Combinada , Metabolismo Energético/efeitos dos fármacos , Humanos , Naltrexona/farmacologia , Antagonistas de Entorpecentes/farmacologia
8.
Diabetes ; 62(2): 490-7, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23048186

RESUMO

The melanocortin-4 receptor (MC4R) is well recognized as an important mediator of body weight homeostasis. Activation of MC4R causes dramatic weight loss in rodent models, and mutations in human are associated with obesity. This makes MC4R a logical target for pharmacological therapy for the treatment of obesity. However, previous studies in rodents and humans have observed a broad array of side effects caused by acute treatment with MC4R agonists, including increased heart rate and blood pressure. We demonstrate that treatment with a highly-selective novel MC4R agonist (BIM-22493 or RM-493) resulted in transient decreases in food intake (35%), with persistent weight loss over 8 weeks of treatment (13.5%) in a diet-induced obese nonhuman primate model. Consistent with weight loss, these animals significantly decreased adiposity and improved glucose tolerance. Importantly, we observed no increases in blood pressure or heart rate with BIM-22493 treatment. In contrast, treatment with LY2112688, an MC4R agonist previously shown to increase blood pressure and heart rate in humans, caused increases in blood pressure and heart rate, while modestly decreasing food intake. These studies demonstrate that distinct melanocortin peptide drugs can have widely different efficacies and side effects.


Assuntos
Fármacos Antiobesidade/uso terapêutico , Sistema Cardiovascular/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Resistência à Insulina , Obesidade/tratamento farmacológico , Peptídeos/uso terapêutico , Receptor Tipo 4 de Melanocortina/agonistas , Redução de Peso/efeitos dos fármacos , alfa-MSH/análogos & derivados , Adiposidade/efeitos dos fármacos , Animais , Pressão Sanguínea/efeitos dos fármacos , Doença Crônica , Ingestão de Alimentos/efeitos dos fármacos , Intolerância à Glucose/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Macaca mulatta , Masculino , Obesidade/etiologia , alfa-MSH/uso terapêutico
9.
J Neurosci ; 31(34): 12189-97, 2011 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-21865462

RESUMO

Leptin regulates body weight in mice by decreasing appetite and increasing sympathetic nerve activity (SNA), which increases energy expenditure in interscapular brown adipose tissue (iBAT). Diet-induced obese mice (DIO) are resistant to the anorectic actions of leptin. We evaluated whether leptin still stimulated sympathetic outflow in DIO mice. We measured iBAT temperature as a marker of SNA. We found that obese hyperleptinemic mice have higher iBAT temperature than mice on regular diet. Conversely, obese leptin-deficient ob/ob mice have lower iBAT temperature. Additionally, leptin increased SNA in obese (DIO and ob/ob) and control mice, despite DIO mice being resistant to anorectic action of leptin. We demonstrated that neurons in the dorsomedial hypothalamus (DMH) of DIO mice mediate the thermogenic responses to hyperleptinemia in obese mammals because blockade of leptin receptors in the DMH prevented the thermogenic effects of leptin. Peripheral Melotan II (MTII) injection increased iBAT temperature, but it was blunted by blockade of DMH melanocortin receptors (MC4Rs) by injecting agouti-related peptide (AgRP) directly into the DMH, suggesting a physiological role of the DMH on temperature regulation in animals with normal body weight. Nevertheless, obese mice without a functional melanocortin system (MC4R KO mice) have an increased sympathetic outflow to iBAT compared with their littermates, suggesting that higher leptin levels drive sympathoexcitation to iBAT by a melanocortin-independent pathway. Because the sympathetic nervous system contributes in regulating blood pressure, heart rate, and hepatic glucose production, selective leptin resistance may be a crucial mechanism linking adiposity and metabolic syndrome.


Assuntos
Tecido Adiposo Marrom/fisiologia , Núcleo Hipotalâmico Dorsomedial/fisiologia , Leptina/fisiologia , Sistema Nervoso Simpático/fisiologia , Termogênese/fisiologia , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/inervação , Animais , Temperatura Corporal/efeitos dos fármacos , Temperatura Corporal/fisiologia , Modelos Animais de Doenças , Núcleo Hipotalâmico Dorsomedial/efeitos dos fármacos , Resistência a Medicamentos/efeitos dos fármacos , Resistência a Medicamentos/fisiologia , Leptina/deficiência , Leptina/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Obesidade/genética , Obesidade/metabolismo , Receptores para Leptina/antagonistas & inibidores , Receptores para Leptina/fisiologia , Sistema Nervoso Simpático/efeitos dos fármacos , Termogênese/efeitos dos fármacos
10.
Am J Physiol Regul Integr Comp Physiol ; 295(5): R1539-45, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18753266

RESUMO

To address the relative contribution of central and peripheral angiotensin II (ANG II) type 1A receptors (AT(1A)) to blood pressure and volume homeostasis, we generated a transgenic mouse model [neuron-specific enolase (NSE)-AT(1A)] with brain-restricted overexpression of AT(1A) receptors. These mice are normotensive at baseline but have dramatically enhanced pressor and bradycardic responses to intracerebroventricular ANG II or activation of endogenous ANG II production. Here our goal was to examine the water and sodium intake in this model under basal conditions and in response to increased ANG II levels. Baseline water and NaCl (0.3 M) intakes were significantly elevated in NSE-AT(1A) compared with nontransgenic littermates, and bolus intracerebroventricular injections of ANG II (200 ng in 200 nl) caused further enhanced water intake in NSE-AT(1A). Activation of endogenous ANG II production by sodium depletion (10 days low-sodium diet followed by furosemide, 1 mg sc) enhanced NaCl intake in NSE-AT(1A) mice compared with wild types. Fos immunohistochemistry, used to assess neuronal activation, demonstrated sodium depletion-enhanced activity in the anteroventral third ventricle region of the brain in NSE-AT(1A) mice compared with control animals. The results show that brain-selective overexpression of AT(1A) receptors results in enhanced salt appetite and altered water intake. This model provides a new tool for studying the mechanisms of brain AT(1A)-dependent water and salt consumption.


Assuntos
Apetite/genética , Ingestão de Líquidos/genética , Receptor Tipo 1 de Angiotensina/genética , Sódio na Dieta/farmacologia , Angiotensina II/sangue , Angiotensina II/farmacologia , Animais , DNA Complementar/biossíntese , DNA Complementar/genética , Eletrólitos/metabolismo , Feminino , Imuno-Histoquímica , Injeções Intraventriculares , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/fisiologia , Fosfopiruvato Hidratase/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Receptor Tipo 1 de Angiotensina/fisiologia , Sódio/deficiência , Sede/fisiologia , Vasoconstritores/sangue , Vasoconstritores/farmacologia , Vasopressinas/metabolismo
11.
PLoS One ; 3(5): e2202, 2008 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-18493584

RESUMO

BACKGROUND: Cannabinoids, the active components of marijuana, stimulate appetite, and cannabinoid receptor-1 (CB1-R) antagonists suppress appetite and promote weight loss. Little is known about how CB1-R antagonists affect the central neurocircuitry, specifically the melanocortin system that regulates energy balance. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that peripherally administered CB1-R antagonist (AM251) or agonist equally suppressed or stimulated feeding respectively in A(y) , which lack a functional melanocortin system, and wildtype mice, demonstrating that cannabinoid effects on feeding do not require melanocortin circuitry. CB1-R antagonist or agonist administered into the ventral tegmental area (VTA) equally suppressed or stimulated feeding respectively, in both genotypes. In addition, peripheral and central cannabinoid administration similarly induced c-Fos activation in brain sites suggesting mediation via motivational dopaminergic circuitry. Amperometry-detected increases in evoked dopamine (DA) release by the CB1-R antagonist in nucleus accumbens slices indicates that AM251 modulates DA release from VTA terminals. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that the effects of cannabinoids on energy balance are independent of hypothalamic melanocortin circuitry and is primarily driven by the reward system.


Assuntos
Canabinoides/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Melanocortinas/fisiologia , Animais , Hipotálamo/efeitos dos fármacos , Hipotálamo/fisiologia , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Sprague-Dawley
12.
Neuropsychopharmacology ; 33(12): 2922-33, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18322467

RESUMO

Olanzapine (OLZ), one of the second-generation atypical antipsychotics (SGAs), has shown relative advantages in patient adherence and outcomes. However, OLZ has also been associated with a higher incidence of weight gain than most other SGAs. Excessive weight gain may in turn contribute to long-term health concerns for some individuals. Zonisamide (ZNS), a medication approved in the United States as an adjunct in the management of epilepsy, has a diverse pharmacological profile, including sodium channel blockade, monoamine enhancement, and inhibition of carbonic anhydrase. ZNS has also been reported to cause weight loss in both humans and rodents. We hypothesized that this profile might be beneficial when co-administered with OLZ. To test this hypothesis, we evaluated the effects of OLZ on body weight, as well as the pathways known to regulate feeding behavior and arousal in the Sprague-Dawley rat. As indicated via c-Fos expression, we found an OLZ-induced activation in the nucleus accumbens and orexin neurons in the lateral hypothalamus. An OLZ-associated development of hyperphagia, weight gain and elevated blood glucose in the rat was also found. These outcomes were attenuated and reversed in the presence of concomitant ZNS. These results suggest the hypothesis that ZNS may effectively treat or prevent weight gain or metabolic changes associated with the SGAs. Future studies of this combination in patients through appropriately designed human clinical studies are encouraged.


Assuntos
Benzodiazepinas/antagonistas & inibidores , Hiperglicemia/tratamento farmacológico , Hiperfagia/tratamento farmacológico , Isoxazóis/farmacologia , Aumento de Peso/efeitos dos fármacos , Animais , Anticonvulsivantes/farmacologia , Anticonvulsivantes/uso terapêutico , Regulação do Apetite/efeitos dos fármacos , Regulação do Apetite/fisiologia , Benzodiazepinas/efeitos adversos , Biomarcadores/metabolismo , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Diabetes Mellitus/induzido quimicamente , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/fisiopatologia , Feminino , Hiperglicemia/induzido quimicamente , Hiperglicemia/fisiopatologia , Hiperfagia/induzido quimicamente , Hiperfagia/fisiopatologia , Região Hipotalâmica Lateral/efeitos dos fármacos , Região Hipotalâmica Lateral/metabolismo , Região Hipotalâmica Lateral/fisiopatologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Isoxazóis/uso terapêutico , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neuropeptídeos/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Núcleo Accumbens/fisiopatologia , Obesidade/induzido quimicamente , Obesidade/tratamento farmacológico , Obesidade/fisiopatologia , Olanzapina , Orexinas , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Sprague-Dawley , Inibidores Seletivos de Recaptação de Serotonina/efeitos adversos , Inibidores Seletivos de Recaptação de Serotonina/antagonistas & inibidores , Resultado do Tratamento , Aumento de Peso/fisiologia , Zonisamida
13.
J Clin Invest ; 117(4): 1088-95, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17404622

RESUMO

The mechanism controlling cell-specific Ang II production in the brain remains unclear despite evidence supporting neuron-specific renin and glial- and neuronal-specific angiotensinogen (AGT) expression. We generated double-transgenic mice expressing human renin (hREN) from a neuron-specific promoter and human AGT (hAGT) from its own promoter (SRA mice) to emulate this expression. SRA mice exhibited an increase in water and salt intake and urinary volume, which were significantly reduced after chronic intracerebroventricular delivery of losartan. Ang II-like immunoreactivity was markedly increased in the subfornical organ (SFO). To further evaluate the physiological importance of de novo Ang II production specifically in the SFO, we utilized a transgenic mouse model expressing a floxed version of hAGT (hAGT(flox)), so that deletions could be induced with Cre recombinase. We targeted SFO-specific ablation of hAGT(flox) by microinjection of an adenovirus encoding Cre recombinase (AdCre). SRA(flox) mice exhibited a marked increase in drinking at baseline and a significant decrease in water intake after administration of AdCre/adenovirus encoding enhanced GFP (AdCre/AdEGFP), but not after administration of AdEGFP alone. This decrease only occurred when Cre recombinase correctly targeted the SFO and correlated with a loss of hAGT and angiotensin peptide immunostaining in the SFO. These data provide strong genetic evidence implicating de novo synthesis of Ang II in the SFO as an integral player in fluid homeostasis.


Assuntos
Angiotensina II/fisiologia , Comportamento de Ingestão de Líquido/fisiologia , Renina/genética , Órgão Subfornical/fisiologia , Angiotensina II/genética , Animais , Ventrículos Cerebrais/efeitos dos fármacos , Ventrículos Cerebrais/fisiologia , Eletrólitos/metabolismo , Homeostase , Humanos , Injeções Intraventriculares , Losartan/administração & dosagem , Losartan/farmacologia , Camundongos , Camundongos Transgênicos , Neurônios/fisiologia , Regiões Promotoras Genéticas
14.
Cell Metab ; 5(3): 181-94, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17339026

RESUMO

Despite high leptin levels, most obese humans and rodents lack responsiveness to its appetite-suppressing effects. We demonstrate that leptin modulates NPY/AgRP and alpha-MSH secretion from the ARH of lean mice. High-fat diet-induced obese (DIO) mice have normal ObRb levels and increased SOCS-3 levels, but leptin fails to modulate peptide secretion and any element of the leptin signaling cascade. Despite this leptin resistance, the melanocortin system downstream of the ARH in DIO mice is over-responsive to melanocortin agonists, probably due to upregulation of MC4R. Lastly, we show that by decreasing the fat content of the mouse's diet, leptin responsiveness of NPY/AgRP and POMC neurons recovered simultaneously, with mice regaining normal leptin sensitivity and glycemic control. These results highlight the physiological importance of leptin sensing in the melanocortin circuits and show that their loss of leptin sensing likely contributes to the pathology of leptin resistance.


Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Leptina/farmacologia , Neurônios/metabolismo , Obesidade/metabolismo , Proteína Relacionada com Agouti , Animais , Núcleo Arqueado do Hipotálamo/citologia , Composição Corporal , Dieta , Gorduras na Dieta/administração & dosagem , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Hipotálamo/metabolismo , Técnicas In Vitro , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Leptina/administração & dosagem , Masculino , Melanocortinas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Neuropeptídeo Y/metabolismo , Pró-Opiomelanocortina/metabolismo , RNA Mensageiro , Transdução de Sinais , Redução de Peso , alfa-MSH/metabolismo
15.
Obesity (Silver Spring) ; 14 Suppl 5: 254S-258S, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17021377

RESUMO

The prevalence of obesity, and the human and economic costs of the disease, creates a need for better therapeutics and better understanding of the physiological processes that balance energy intake and energy expenditure. Leptin is the primary signal from energy stores and exerts negative feedback effects on energy intake. In common obesity, leptin loses the ability to inhibit energy intake and increase energy expenditure; this is termed leptin resistance. This review discusses the evidence in support of leptin resistance in mouse models and humans and the possible mechanisms of leptin resistance.


Assuntos
Tecido Adiposo/metabolismo , Metabolismo Energético/fisiologia , Leptina/metabolismo , Obesidade/metabolismo , Transdução de Sinais , Animais , Ingestão de Energia/fisiologia , Humanos , Camundongos , Obesidade/fisiopatologia
16.
Circ Res ; 99(10): 1125-31, 2006 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-17053195

RESUMO

The subfornical organ (SFO) of the brain has long been considered a critical integrating center for the cardiovascular actions of the renin-angiotensin system (RAS). Early reports of angiotensin II (Ang II) immunoreactivity in the SFO and its neural projections to downstream cardiovascular nuclei raised the possibility that Ang II is produced locally and functions as a putative neurotransmitter in these circuits. However, evidence of functionally significant de novo synthesis of Ang II in the SFO has been lacking. Here, implementing spatiotemporally restricted gene ablation by way of the Cre recombinase/loxP system, we provide the first direct evidence that the local RAS in the SFO has a critical role in blood pressure regulation. Using a transgenic mouse harboring an angiotensinogen (AGT) gene modified for Cre-mediated deletion (hAGT(flox)), in combination with gene transfer of an adenovirus encoding Cre targeted to the SFO, we show that deletion of the Ang II substrate in this brain region nearly abolishes the pressor and bradycardic effects of renin infused in the CNS. Immunohistochemical analyses verified intense and restricted expression of Cre in the SFO, which paralleled the decrease in AGT expression selectively in this site. Further physiological studies confirmed the integrity of central angiotensinergic and nonangiotensinergic cardiovascular response systems in the Cre-treated mice. In addition to establishing that AGT expression in the SFO and its local conversion to Ang II has a profound effect on blood pressure, this study provides proof-of-principle of the utility of this approach for dissecting the brain RAS and other complex systems in CNS cardiovascular circuits.


Assuntos
Angiotensinogênio/genética , Pressão Sanguínea/fisiologia , Órgão Subfornical/fisiologia , Adenoviridae/genética , Angiotensina II/biossíntese , Angiotensinogênio/sangue , Angiotensinogênio/deficiência , Angiotensinogênio/metabolismo , Animais , Feminino , Vetores Genéticos/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Recombinases/genética , Recombinases/metabolismo , Renina/antagonistas & inibidores , Renina/farmacologia , Órgão Subfornical/efeitos dos fármacos , Órgão Subfornical/metabolismo , Transfecção
17.
Endocrine ; 29(1): 33-48, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16622291

RESUMO

With an ever-growing population of obese people as well as comorbidities associated with obesity, finding effective weight loss strategies is more imperative than ever. One of the challenges in curbing the obesity crisis is designing successful strategies for long-term weight loss and weight-loss maintenance. Currently, weight-loss strategies include promotion of therapeutic lifestyle changes (diet and exercise), pharmacological therapy, and bariatric surgery. This review focuses on several pharmacological targets that activate central nervous system pathways that normally limit food intake and body weight. Though it is likely that no single therapy will prove effective for everyone, this review considers several recent pre-clinical targets, and several compounds that have been in human clinical trials.


Assuntos
Fármacos Antiobesidade/uso terapêutico , Hipotálamo/fisiologia , Obesidade/tratamento farmacológico , Obesidade/fisiopatologia , Transdução de Sinais/fisiologia , Proteínas Quinases Ativadas por AMP , Proteína Relacionada com Agouti , Fármacos Antiobesidade/farmacologia , Regulação do Apetite/efeitos dos fármacos , Regulação do Apetite/fisiologia , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Moduladores de Receptores de Canabinoides/fisiologia , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/fisiopatologia , Fator Neurotrófico Ciliar/fisiologia , Metabolismo Energético , Frutose/análogos & derivados , Frutose/uso terapêutico , Humanos , Hormônios Hipotalâmicos/fisiologia , Hipotálamo/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular , Melaninas/fisiologia , Complexos Multienzimáticos/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Neuropeptídeo Y/fisiologia , Hormônios Hipofisários/fisiologia , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas/fisiologia , Receptores de Melanocortina/fisiologia , Topiramato , alfa-MSH/fisiologia
18.
Physiol Genomics ; 18(1): 25-32, 2004 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-15069166

RESUMO

The Cre/loxP system has shown promise for investigating genes involved in nervous system function and pathology, although its application for studying central neural regulation of cardiovascular function and disease has not been explored. Here, we report for the first time that recombination of loxP-flanked genes can be achieved in discrete cardiovascular regulatory nuclei of adult mouse brain using targeted delivery of adenovirus (Ad) or feline immunodeficiency virus (FIV) bearing Cre recombinase (Ad-Cre, FIV-Cre). Single stereotaxic microinjections of Ad-Cre or FIV-Cre into specific nuclei along the subfornical organ-hypothalamic-hypophysial and brain stem-parabrachial axes resulted in robust and highly localized gene deletion as early as 7 days and for as long as 3 wk in a reporter mouse model in which Cre recombinase activates beta-galactosidase expression. An even greater selectivity in Cre-mediated gene deletion could be achieved in unique subpopulations of cells, such as vasopressin-synthesizing magnocellular neurons, by delivering Ad-Cre via retrograde transport. Moreover, Ad-Cre and FIV-Cre induced gene recombination in differential cell populations within these cardiovascular nuclei. FIV-Cre infection resulted in LacZ activation selectively in neurons, whereas both neuronal and glial cell types underwent gene recombination upon infection with Ad-Cre. These results establish the feasibility of using a combination of viral and Cre/loxP technologies to target specific cardiovascular nuclei in the brain for conditional gene modification and suggest the potential of this approach for determining the functional role of genes within these sites.


Assuntos
Encéfalo/metabolismo , Deleção de Genes , Regulação da Expressão Gênica/fisiologia , Marcação de Genes/métodos , Integrases/genética , Recombinação Genética , Sequências Reguladoras de Ácido Nucleico , Sistema Renina-Angiotensina/fisiologia , Proteínas Virais/genética , Adenoviridae/genética , Animais , Células Cultivadas/metabolismo , Citomegalovirus/genética , Genes Reporter , Genes Sintéticos , Vetores Genéticos/genética , Vírus da Imunodeficiência Felina/genética , Óperon Lac , Camundongos , Camundongos Transgênicos , Microinjeções , Neurônios/metabolismo , Regiões Promotoras Genéticas/genética , Sistema Renina-Angiotensina/genética , Órgão Subfornical/metabolismo , Núcleo Supraóptico/metabolismo
19.
Circ Res ; 91(11): 1038-45, 2002 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-12456490

RESUMO

Angiotensin II (Ang II) has profound effects in the central nervous system (CNS), including promotion of thirst, regulation of vasopressin secretion, and modulation of sympathetic outflow. Despite its importance in cardiovascular and volume homeostasis, angiotensinergic mechanisms are incompletely understood in the CNS. Recently, a novel signaling mechanism for Ang II involving reactive oxygen species (ROS) has been identified in a variety of peripheral tissues, but the involvement of ROS as second messengers in Ang II-mediated signaling in the CNS has not been reported. The hypothesis that superoxide is a key mediator of the actions of Ang II in the CNS was tested in mice using adenoviral vector-mediated expression of superoxide dismutase (AdSOD). Changes in blood pressure, heart rate, and drinking elicited by injection of Ang II in the CNS were abolished by prior treatment with AdSOD in the brain, whereas the cardiovascular responses to carbachol, another central vasopressor agent, were unaffected. In addition, Ang II stimulated superoxide generation in primary CNS cell cultures, and this was prevented by the Ang II receptor (Ang II type 1 subtype) antagonist losartan or AdSOD. These results identify a novel signaling mechanism mediating the actions of Ang II in the CNS. Dysregulation of this signaling cascade may be important in hypertension and heart failure triggered by Ang II acting in the CNS.


Assuntos
Angiotensina II/fisiologia , Sistema Nervoso Central/metabolismo , Transdução de Sinais/fisiologia , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Angiotensina II/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Células Cultivadas , Sistema Nervoso Central/efeitos dos fármacos , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Comportamento de Ingestão de Líquido/fisiologia , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Humanos , Hipotálamo/citologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Injeções Intra-Arteriais , Injeções Intraventriculares , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/enzimologia , Agonistas Muscarínicos/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Superóxido Dismutase/genética , Superóxido Dismutase/farmacologia , Transgenes
20.
Hypertension ; 39(2 Pt 2): 603-8, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11882616

RESUMO

The systemic renin-angiotensin system (RAS) plays a critical role in cardiovascular (CV) homeostasis. All components of the RAS are also known to be produced cell-specifically within specific brain regions, although the role of the brain RAS relative to the systemic RAS has remained a puzzle due to the difficulty of dissecting these two systems. Selectively targeting these regions with genes that modify the RAS could help unravel this puzzle. We compared the ability of adenovirus (Ad) and lentivirus (feline immunodeficiency virus, FIV) vectors to mediate gene delivery in vivo to the supraoptic nucleus (SON) and subfornical organ (SFO), two important CV control regions known to express the various RAS genes. SON or SFO of adult C57BL/6 mice (n=37) were stereotaxically injected with replication-deficient recombinant Ad or FIV harboring a beta-galactosidase (beta-gal) reporter gene. At 1, 3, or 8 weeks post-injection, brain sections were processed for beta-Gal activity, double immunofluorescence to verify cell-type specificity of viral transduction, or immunohistochemical detection of inflammatory mediators. Our results demonstrate that: (1) murine SFO and SON can be selectively targeted for gene transfer in vivo;(2) FIV mediated neuron-specific gene delivery, whereas Ad transduced both neuronal and glial cell types in SFO and SON; (3) Ad injected into the SON transduced neurons within the SFO through retrograde transport, whereas FIV did not; (4) beta-gal activity remained stable for 3 weeks but then declined by 8 weeks with Ad, while minimal decline occurred with FIV; (5) FIV did not cause inflammatory responses, whereas infiltrate was detectable in Ad-injected SFO and SON. These vectors are potentially important tools for dissecting the cell- and site-specific components of the brain RAS and other important CV regulatory systems within this circuitry, and may have therapeutic applications for centrally mediated CV diseases.


Assuntos
Encéfalo/fisiologia , Adenoviridae/genética , Animais , Feminino , Técnicas de Transferência de Genes , Vetores Genéticos/genética , Vírus da Imunodeficiência Felina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL
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