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We sought to investigate whether RVLM iNOS activity and oxidative profile may participate in the reduction of sympathetic responsiveness in swimming trained normotensive rats. Sedentary (S) and swimming trained (T) Wistar male rats chronically instrumented with an arterial catheter and guide cannula into the RVLM were submitted to continuous pressure and heart rate (HR) recordings and determination of autonomic control (power spectral analysis) before and after unilateral RVLM iNOS inhibition (aminoguanidine, 250 pmol/100 nL). Other S and T rats received local l-glutamate microinjection (5 nmol/100 nL). In separate S and T groups not submitted to brainstem cannulation, fresh bilateral RVLM punchs were collected for iNOS gene expression (qPCR); reduced glutathione and lipid peroxidation quantification (spectrophotometry); iron-reducing antioxidant (FRAP) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTSË+) scavenger assays. iNOS gene expression was confirmed in fixed RVLM slices (immunofluorescence). T rats exhibited resting bradycardia, lower sympathovagal balance, reduced RVLM iNOS gene/protein expression and higher antioxidant capacity. Decreased iNOS expression was positively correlated with reduced HR. Pressor and tachycardic response to l-Glutamate were smaller in T rats. Aminoguanidine microinjection reduced sympathetic activity in S rats but did not change it in T rats expressing reduced RVLM iNOS content. Our data indicate that iNOS, expressed in the RVLM of normotensive male rats, has tonic effects on sympathetic activity and that swimming training is an efficient tool to reduce iNOS expression and augment the antioxidant defense, thus reducing glutamatergic responsiveness and sympathetic drive to cardiovascular effectors.
Assuntos
Sistema Nervoso Autônomo/metabolismo , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Bulbo/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Estresse Oxidativo/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Sistema Nervoso Autônomo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Guanidinas/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Peroxidação de Lipídeos/fisiologia , Masculino , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Estresse Oxidativo/efeitos dos fármacos , Ratos , NataçãoRESUMO
Ureases are microbial virulence factors either because of the enzymatic release of ammonia or due to many other non-enzymatic effects. Here we studied two neurotoxic urease isoforms, Canatoxin (CNTX) and Jack Bean Urease (JBU), produced by the plant Canavalia ensiformis, whose mechanisms of action remain elusive. The neurotoxins provoke convulsions in rodents (LD50 â¼2 mg/kg) and stimulate exocytosis in cell models, affecting intracellular calcium levels. Here, electrophysiological and brain imaging techniques were applied to elucidate their mode of action. While systemic administration of the toxins causes tonic-clonic seizures in rodents, JBU injected into rat hippocampus induced spike-wave discharges similar to absence-like seizures. JBU reduced the amplitude of compound action potential from mouse sciatic nerve in a tetrodotoxin-insensitive manner. Hippocampal slices from CNTX-injected animals or slices treated in vitro with JBU failed to induce long term potentiation upon tetanic stimulation. Rat cortical synaptosomes treated with JBU released L-glutamate. JBU increased the intracellular calcium levels and spontaneous firing rate in rat hippocampus neurons. MicroPET scans of CNTX-injected rats revealed increased [18]Fluoro-deoxyglucose uptake in epileptogenesis-related areas like hippocampus and thalamus. Curiously, CNTX did not affect voltage-gated sodium, calcium or potassium channels currents, neither did it interfere on cholinergic receptors, suggesting an indirect mode of action that could be related to the ureases' membrane-disturbing properties. Understanding the neurotoxic mode of action of C. ensiformis ureases could help to unveil the so far underappreciated relevance of these toxins in diseases caused by urease-producing microorganisms, in which the human central nervous system is affected.
Assuntos
Canavalia/química , Síndromes Neurotóxicas/etiologia , Proteínas de Plantas/toxicidade , Toxinas Biológicas/toxicidade , Urease/toxicidade , Animais , Convulsivantes/isolamento & purificação , Convulsivantes/toxicidade , Feminino , Masculino , Camundongos , Sistema Nervoso/efeitos dos fármacos , Sistema Nervoso/patologia , Síndromes Neurotóxicas/fisiopatologia , Proteínas de Plantas/isolamento & purificação , Ratos , Ratos Wistar , Toxinas Biológicas/isolamento & purificação , Urease/isolamento & purificação , Xenopus laevisRESUMO
Purpose: Dysregulation of glutamatergic neurotransmission (GN) is linked to sympathetic-respiratory overactivity and hypertension. We investigated whether maternal protein restriction is able to alter GN into the nucleus of the solitary tract (NTS) in adult offspring.Methods: Wistar rat dams were fed with control (NP; 17% protein) or low-protein (LP; 8% protein) diet during pregnancy and lactation, and their offspring were evaluated at 70-90d old. Direct measurements of mean arterial pressure (MAP), heart rate (HR), respiratory frequency (RF) and respiratory (RV) and cardiac (CV) variabilities were assessed in consciousness. The evaluation of GN into NTS over cardiovascular system were assessed by microinjections of unilateral glutamate (L-glu 0.5 nmol/100nL) and bilateral kynurenic acid (Kyn 2.5 nmol/50nL). The NP and LP groups were compared using unpaired Student's t-test where p < 0.05 was considered signiï¬cant.Results: The LP exhibited higher MAP at rest (p = 0.03) and after L-glu microinjection (p = 0.04), as well as an increase over HR after Kyn microinjection when compared to the NP (p = 0.049). In the RV, the LP group showed an increase of the component-standard deviation 1 (p = 0.037) at rest. In the CV, the LP presented an increase of the low frequency (LF) component of the pulse interval (PI) (p = 0.034), a decrease of high frequency (HF) of the PI (p = 0.034), beyond an increased LF/HF ratio of the PI (p = 0.027) when compared to the NP. The kynurenic acid microinjection did not produce changes in RV or CV (p > 0.05).Conclusions: Altered GN into the NTS may contribute to augmented blood pressure in protein-restricted offspring.
Assuntos
Sistema Cardiovascular , Ácido Glutâmico , Animais , Pressão Sanguínea , Estado de Consciência , Dieta com Restrição de Proteínas , Feminino , Ácido Glutâmico/metabolismo , Frequência Cardíaca/fisiologia , Humanos , Microinjeções , Gravidez , Ratos , Ratos Wistar , Núcleo Solitário/metabolismoRESUMO
Abnormal calcium influx and glutamatergic excitotoxicity have been extensively associated with neuronal death in Huntington's disease (HD), a genetic movement disorder. Currently, there is no effective treatment for this fatal condition. The neurotoxin Phα1ß has demonstrated therapeutic effects as a calcium channel blocker, for example during pain control. However, little is known about its neuroprotective effect in HD. Herein, we investigated if Phα1ß is effective in inhibiting neuronal cell death in the BACHD mouse model for HD. We performed intrastriatal injection of Phα1ß in WT and BACHD mice. No side effects or unusual behaviors were observed upon Phα1ß administration. Using three different motor behavior tests, we observed that injection of the toxin in BACHD mice greatly improved the animals' motor-force as seen in the Wire-hang test, and also the locomotor performance, according to the Open field test. NeuN labeling for mature neuron detection revealed that Phα1ß toxin promoted neuronal preservation in the striatum and cortex, when injected locally. Intrastriatal injection of Phα1ß was not able to preserve neurons from the spinal cord and also not revert muscle atrophy in BACHD mice. Finally, we observed that Phα1ß might, at least in part, exert its protective effect by decreasing L-glutamate, measured in cerebrospinal fluid. Our data provide evidence of a novel neuroprotector effect of Phα1ß, paving a path for the development of new approaches to treat HD motor symptoms.
Assuntos
Doença de Huntington/tratamento farmacológico , Fármacos Neuroprotetores/administração & dosagem , Venenos de Aranha/administração & dosagem , Animais , Modelos Animais de Doenças , Ácido Glutâmico/metabolismo , Doença de Huntington/patologia , Camundongos , Camundongos Transgênicos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , Neurônios/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologiaRESUMO
ß-Lactam antibiotics such as ceftriaxone, are potent stimulators of the expression of l-glutamate transporter GLT-1 and may exert neuroprotective effects when chronically used in rats and mice. In this study, we used two animal models to test the neurological effect of subchronic treatment with ceftriaxone: experimental acute glaucoma in Wistar rats and induction of acute seizures with pentylenetetrazole in mice. We also assessed the performance of mice in the rotarod to calculate therapeutic indexes and exploratory activity in the open field. Our results showed that subchronic use of ceftriaxone was neuroprotective in both models, reducing injury in acute ischemia and ischemia/reperfusion in specific layers of retina and leading to a decrease in the seizure severity score. In behavioral experiments, we observed that ceftriaxone increased hyperactivity followed by a decrease in exploratory behavior in the open field, and there was no motor impairment in the rotarod test. We conclude that ceftriaxone may be useful as a tool in the development of new neuroprotective drugs targeting diseases which present a possible dysfunction in the balance of glutamatergic neurotransmission.
Assuntos
Antibacterianos/administração & dosagem , Ceftriaxona/administração & dosagem , Convulsivantes/farmacologia , Glaucoma/fisiopatologia , Fármacos Neuroprotetores/administração & dosagem , Convulsões/prevenção & controle , Tetrazóis/farmacologia , Doença Aguda , Animais , Comportamento Animal/efeitos dos fármacos , Masculino , Camundongos , Ratos , Ratos WistarRESUMO
BACKGROUND: L-Glutamate (L-Glu), the major excitatory neurotransmitter in the mammalian Central Nervous System (CNS), is essential to cognitive functions. However, when L-Glu is accumulated in large concentrations at the synaptic cleft, it can induce excitotoxicity that results in secondary damage implicated in many neurological disorders. Current therapies for the treatment of neurological disorders are ineffective and have side effects associated with their use; therefore, there is a need to develop novel treatments. In this regard, previous studies have shown that neuroactive compounds obtained from the venom of the spider Parawixia bistriata have neuroprotective effects in vitro and in vivo. In this sense, this work aimed to evaluate potential neuroprotective effects of fraction RT10, obtained from this spider venom, on primary cultures of neuron and glial cells subjected to glutamate excitotoxicity insults. METHODS: Primary cultures of neurons and glia were obtained from the cerebral tissue of 1-day-old postnatal Wistar rats. After 7 days in vitro (DIV), the cultures were incubated with fraction RT10 (0.002; 0.02; 0.2 and 2 µg/µL) or riluzole (100 µM) for 3-hours before application of 5 mM L-Glu. After 12 hours, the resazurin sodium salt (RSS) test was applied to measure metabolic activity and proliferation of living cells, whereas immunocytochemistry for MAP2 was performed to measure neuronal survival. In addition, the cells were immunolabeled with NeuN and GFAP in baseline conditions. RESULTS: In the RSS tests, we observed that pre-incubation with RT10 before the excitotoxic insults from L-Glu resulted in neuroprotection, shown by a 10% reduction in the cell death level. RT10 was more effective than riluzole, which resulted in a cell-death reduction of 5%. Moreover, qualitative analysis of neuronal morphology (by MAP2 staining, expressed as fluorescence intensity (FI), an indirect measure of neuronal survival) indicate that RT10 reduced the toxic effects of L-Glu, as shown by a 38 % increase in MAP2 fluorescence when compared to L-Glu insult. On the other hand, the riluzole treatment resulted in 17% increase of MAP2 fluorescence; therefore, the neuroprotection from RT10 was more efficacious. CONCLUSION: RT10 fraction exhibits neuroprotective effects against L-Glu excitotoxicity in neuron-glia cultured in vitro.
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Background: L-Glutamate (L-Glu), the major excitatory neurotransmitter in the mammalian Central Nervous System (CNS), is essential to cognitive functions. However, when L-Glu is accumulated in large concentrations at the synaptic cleft, it can induce excitotoxicity that results in secondary damage implicated in many neurological disorders. Current therapies for the treatment of neurological disorders are ineffective and have side effects associated with their use; therefore, there is a need to develop novel treatments. In this regard, previous studies have shown that neuroactive compounds obtained from the venom of the spider Parawixia bistriata have neuroprotective effects in vitro and in vivo. In this sense, this work aimed to evaluate potential neuroprotective effects of fraction RT10, obtained from this spider venom, on primary cultures of neuron and glial cells subjected to glutamate excitotoxicity insults. Methods: Primary cultures of neurons and glia were obtained from the cerebral tissue of 1-day-old postnatal Wistar rats. After 7 days in vitro (DIV), the cultures were incubated with fraction RT10 (0.002; 0.02; 0.2 and 2 µg/µL) or riluzole (100 µM) for 3-hours before application of 5 mM L-Glu. After 12 hours, the resazurin sodium salt (RSS) test was applied to measure metabolic activity and proliferation of living cells, whereas immunocytochemistry for MAP2 was performed to measure neuronal survival. In addition, the cells were immunolabeled with NeuN and GFAP in baseline conditions. Results: In the RSS tests, we observed that pre-incubation with RT10 before the excitotoxic insults from L-Glu resulted in neuroprotection, shown by a 10% reduction in the cell death level. RT10 was more effective than riluzole, which resulted in a cell-death reduction of 5%. Moreover, qualitative analysis of neuronal morphology (by MAP2 staining, expressed as fluorescence intensity (FI), an indirect measure of neuronal survival)...(AU)
Assuntos
Animais , Ratos , Ratos Wistar , Neuroglia/química , Glutamatos/análise , Glutamatos/toxicidade , Venenos de Aranha/uso terapêutico , Fármacos Neuroprotetores/administração & dosagem , Neurotoxinas/análiseRESUMO
BACKGROUND: Obesity is a chronic and multifactorial disease characterized by increased adipose tissue. In females, obesity leads to reduced ovulation and lower chances of conception in diseases like polycystic ovary syndrome, making it important to characterize complementary medicine to attenuate such deleterious effects. Therefore, the aim of this study was to assess the effects of a hydroethanolic extract from Syzigium cumini leaves in female reproductive impairments present in the obesity model of neonatal L-monosodium glutamate injection. METHODS: Newborn Wistar rats received saline (CTRL) or L-monosodium glutamate 4 mg/g BW (MSG). At 90 days of age, CTRL and some MSG rats received saline, while others received hydroethanolic extract of S. cumini leaves (HESc 500 mg/kg/day, MSG-Syz group) for 30 consecutive days. Estrous cycle was determined by daily vaginal washes. On days 26 and 28 of treatment, oral glucose tolerance test and blood collection were performed for biochemical assessment. At the end, animals were euthanized during estrous phase; blood was collected to measure sex hormones and organs collected for weighing and histological evaluation. RESULTS: MSG-Syz showed reduced Lee Index, retroperitoneal fat pads and restored gluco-insulin axis. Moreover, HESc treatment reduced serum cholesterol levels when compared to MSG. Treatment with HESc did not restore the oligociclicity observed in obese animals, though MSG-Syz reestablished ovarian follicle health back to CTRL levels, with proliferating primordial follicles - these effects were followed by a decrease on periovarian adipocyte area. CONCLUSIONS: This is the first report to show the reversibility of the reproductive dysfunctions seen in MSG female rats through ethnopharmacological treatment. Moreover, it expands the use of HESc as a prominent tool to treat metabolic and reproductive disorders. Finally, we provide novel evidence that, without a functioning hypothalamus-pituitary-gonads axis, metabolic improvement is ineffective for estrous cyclicity, but critical for ovarian follicle health.
Assuntos
Obesidade/tratamento farmacológico , Extratos Vegetais/uso terapêutico , Síndrome do Ovário Policístico/tratamento farmacológico , Syzygium , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Animais , Glicemia/metabolismo , Colesterol/metabolismo , Feminino , Hipotálamo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Obesidade/induzido quimicamente , Obesidade/metabolismo , Ovário/efeitos dos fármacos , Ovário/metabolismo , Hipófise , Folhas de Planta , Síndrome do Ovário Policístico/metabolismo , Ratos Wistar , Glutamato de SódioRESUMO
Monosodium l-glutamate (MSG)-induced obesity is a useful model for non-alcoholic fatty liver disease (NAFLD) studies. However, there is limited data on its initiation and progression. Thus, this study aimed to characterize the onset of metabolic and histopathological features of NAFLD and its progression to non-alcoholic steatohepatitis (NASH) in this model. To perform this study, Swiss mice pups were neonatally injected with MSG (4 g/kg/day, s.c.) or equiosmolar saline and followed up to 60, 120 or 180 days old. At each age, blood, liver, as well as periepididymal and retroperitoneal fat pads were collected for morphometric, biochemical and histological analyses, the later according to NAFLD activity score. MSG mice presented hypertriglyceridemia and central obesity at all ages, but peripheral insulin-resistance was verified only in 120- and 180-day-old mice. Hepatic total fat and triglycerides content were higher in MSG mice at all ages. Accordingly, histopathological analysis showed that 60-day-old MSG mice had microvesicular steatosis with occasional ballooning, which evolved into NASH from 120 days old. Retroperitoneal fat accumulation was the only variable to independently correlate with NAFLD activity total score upon multivariate analysis (R 2=71.45%). There were no differences in IL-6 and TNF-α serum levels among groups. Overall, this study shows that NAFLD is a precocious outcome in MSG-obese mice, whereas the period comprised between 60 and 120 days old seems to be a crucial metabolic window for comprehending pathophysiological events involved in NAFLD-to-NASH progression in this model.
Assuntos
Modelos Animais de Doenças , Hipertrigliceridemia/metabolismo , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/complicações , Gordura Abdominal/metabolismo , Adolescente , Adulto , Fatores Etários , Idade de Início , Animais , Animais Recém-Nascidos , Progressão da Doença , Feminino , Humanos , Hipertrigliceridemia/diagnóstico , Hipertrigliceridemia/etiologia , Metabolismo dos Lipídeos , Fígado/metabolismo , Masculino , Camundongos , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/patologia , Obesidade/induzido quimicamente , Obesidade/metabolismo , Glutamato de Sódio/toxicidade , Adulto JovemRESUMO
L-Glutamate (L-Glu), the major excitatory neurotransmitter in the mammalian Central Nervous System (CNS), is essential to cognitive functions. However, when L-Glu is accumulated in large concentrations at the synaptic cleft, it can induce excitotoxicity that results in secondary damage implicated in many neurological disorders. Current therapies for the treatment of neurological disorders are ineffective and have side effects associated with their use; therefore, there is a need to develop novel treatments. In this regard, previous studies have shown that neuroactive compounds obtained from the venom of the spider Parawixia bistriata have neuroprotective effects in vitro and in vivo. In this sense, this work aimed to evaluate potential neuroprotective effects of fraction RT10, obtained from this spider venom, on primary cultures of neuron and glial cells subjected to glutamate excitotoxicity insults. Methods: Primary cultures of neurons and glia were obtained from the cerebral tissue of 1-day-old postnatal Wistar rats. After 7 days in vitro (DIV), the cultures were incubated with fraction RT10 (0.002; 0.02; 0.2 and 2 µg/µL) or riluzole (100 µM) for 3-hours before application of 5 mM L-Glu. After 12 hours, the resazurin sodium salt (RSS) test was applied to measure metabolic activity and proliferation of living cells, whereas immunocytochemistry for MAP2 was performed to measure neuronal survival. In addition, the cells were immunolabeled with NeuN and GFAP in baseline conditions. Results: In the RSS tests, we observed that pre-incubation with RT10 before the excitotoxic insults from L-Glu resulted in neuroprotection, shown by a 10% reduction in the cell death level. RT10 was more effective than riluzole, which resulted in a cell-death reduction of 5%. Moreover, qualitative analysis of neuronal morphology (by MAP2 staining, expressed as fluorescence intensity (FI), an indirect measure of neuronal survival) indicate that RT10 reduced the toxic effects of L-Glu, as shown by a 38 % increase in MAP2 fluorescence when compared to L-Glu insult. On the other hand, the riluzole treatment resulted in 17% increase of MAP2 fluorescence; therefore, the neuroprotection from RT10 was more efficacious. Conclusion: RT10 fraction exhibits neuroprotective effects against L-Glu excitotoxicity in neuron-glia cultured in vitro.(AU)
Assuntos
Venenos de Aranha , Neuroproteção , Neurotransmissores , Agonistas de Aminoácidos Excitatórios , Estudos de Avaliação como AssuntoRESUMO
Vasopressin (AVP) and oxytocin (OT) are essential for the control of extracellular fluid osmolality and volume. Secretion of these hormones is modulated by several mechanisms, including NMDA and AMPA L-glutamate receptors in magnocellular cells of paraventricular (PVN) and supraoptic (SON) hypothalamic nuclei. Thus, to better understand the participation of L-glutamate on the neuroendocrine control of AVP and OT, this work evaluated the effects of intracerebroventricular (icv) NMDA and AMPA receptor antagonists on plasma AVP and OT levels induced by extracellular volume expansion (EVE). Cannulated rats received icv NMDA (AP5) and AMPA (NBQX) antagonists in 10 and 30nmol/5µl/rat doses and were subjected to either isotonic (0.15 M NaCl, 2ml/100g) or hypertonic (0.30 M NaCl, 2ml/100g) EVE. Blood samples were collected for plasma AVP and OT determination. Isotonic EVE did not change plasma AVP and OT levels, but hypertonic EVE increased both AVP and OT plasma levels. AP5 reduced plasma AVP, but it did not change the OT level induced by hypertonic EVE. On the other hand, NBQX reduced plasma OT, but did not alter the AVP plasma level. Our data shows that L-glutamate controls the secretion of neurohypophyseal hormones through the NMDA receptor for AVP release, and through the AMPA receptor for OT release, both in response to hypertonic EVE. This article is protected by copyright. All rights reserved.
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Nowadays, chronic kidney disease (CKD) is considered a worldwide public health problem. CKD is a term used to describe a set of pathologies that structurally and functionally affect the kidney, it is mostly characterized by the progressive loss of kidney function. Current therapeutic approaches are insufficient to avoid the development of this disease, which highlights the necessity of developing new strategies to reverse or at least delay CKD progression. Kidney is highly dependent on mitochondrial homeostasis and function, consequently, the idea that mitochondrial pathologies could play a pivotal role in the genesis and development of kidney diseases has risen. Although many research groups have recently published studies of mitochondrial function in acute kidney disease models, the existing information about CKD is still limited, especially in renal mass reduction (RMR) models. This paper focuses on reviewing current experimental information about the bioenergetics, dynamics (fission and fusion processes), turnover (mitophagy and biogenesis) and redox mitochondrial alterations in RMR, to discuss and integrate the mitochondrial changes triggered by nephron loss, as well as its relationship with loss of kidney function in CKD, in these models. Understanding these mechanisms would allow us to design new therapies that target these mitochondrial alterations.
Assuntos
Mitocôndrias/fisiologia , Insuficiência Renal Crônica/fisiopatologia , Animais , Progressão da Doença , Metabolismo Energético , Humanos , Rim/fisiologia , Renovação Mitocondrial , OxirreduçãoRESUMO
KEY MESSAGE: The function and components of L-glutamate signaling pathways in plants have just begun to be elucidated. Here, using a combination of genetic and biochemical strategies, we demonstrated that a MAPK module is involved in the control of root developmental responses to this amino acid. Root system architecture plays an essential role in plant adaptation to biotic and abiotic factors via adjusting signal transduction and gene expression. L-Glutamate (L-Glu), an amino acid with neurotransmitter functions in animals, inhibits root growth, but the underlying genetic mechanisms are poorly understood. Through a combination of genetic analysis, in-gel kinase assays, detailed cell elongation and division measurements and confocal analysis of expression of auxin, quiescent center and stem cell niche related genes, the critical roles of L-Glu in primary root growth acting through the mitogen-activated protein kinase 6 (MPK6) and the dual specificity serine-threonine-tyrosine phosphatase MKP1 could be revealed. In-gel phosphorylation assays revealed a rapid and dose-dependent induction of MPK6 and MPK3 activities in wild-type Arabidopsis seedlings in response to L-Glu. Mutations in MPK6 or MKP1 reduced or increased root cell division and elongation in response to L-Glu, possibly modulating auxin transport and/or response, but in a PLETHORA1 and 2 independent manner. Our data highlight MPK6 and MKP1 as components of an L-Glu pathway linking the auxin response, and cell division for primary root growth.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/fisiologia , Ácido Glutâmico/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Raízes de Plantas/enzimologia , Proteínas Tirosina Fosfatases/metabolismo , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/biossíntese , Proliferação de Células/efeitos dos fármacos , Indução Enzimática/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácidos Indolacéticos/farmacologia , Proteínas de Membrana Transportadoras/metabolismo , Meristema/efeitos dos fármacos , Meristema/enzimologia , Proteínas Quinases Ativadas por Mitógeno/biossíntese , Mutação/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Proteínas Tirosina Fosfatases/biossíntese , Fatores de Transcrição/metabolismoRESUMO
OBJECTIVES: Obesity is a metabolic and hormonal disorder with serious social and psychological impacts. There is a close relationship among obesity, neuroendocrine homeostasis and behavioral patterns. However, few data are available in the literature regarding this subject. This study assessed behavior and memory of adult obese rats by monosodium l-glutamate (MSG) neonatal treatment or highly palatable dietary treatment. METHODS: MSG obesity was induced by subcutaneous injections of MSG (4 mg/g) during the first 5 days of life (Ob-MSG); control group (C-MSG), received saline solution equimolar. Both groups were fed with commercial chow. To induce dietary obesity, 21-day-old rats were assigned to two experimental diets: highly palatable diet (Ob-Diet) and control diet (C-Diet) composed of commercial chow. Ninety-day-old animals were submitted to behavioral assessment by the open-field test and short- and long-term memory by the object recognition test. Biometric variables were obtained, the Lee index was calculated and mass of retroperitoneal and perigonadal fat pads was measured. Furthermore, an altered behavioral profile was investigated by quantification of plasmatic corticosterone, expression, and activity of hypothalamic extracellular signal-regulated kinase protein (ERK) 1 and 2. RESULTS: Increased Lee index and fat pads were observed in Ob-MSG and Ob-Diet groups. Ob-MSG presented a higher level of anxiety and impaired long-term memory compared to C-MSG, while there was no difference between Ob-Diet and C-Diet. The Ob-MSG group presented a higher level of plasmatic corticosterone and increased phosphorylation of hypothalamic ERK1 and 2. DISCUSSION: Both treatments induced obesity but only Ob-MSG showed altered behavioral parameters, which is related to increased concentration of corticosterone and hypothalamic ERK1 and 2 activation.
Assuntos
Corticosterona/sangue , Modelos Animais de Doenças , Hipotálamo/metabolismo , Sistema de Sinalização das MAP Quinases , Consolidação da Memória , Neurônios/metabolismo , Obesidade/metabolismo , Animais , Animais Recém-Nascidos , Comportamento Animal/efeitos dos fármacos , Corticosterona/agonistas , Ativação Enzimática/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Hipotálamo/enzimologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Consolidação da Memória/efeitos dos fármacos , Memória de Longo Prazo/efeitos dos fármacos , Memória de Curto Prazo/efeitos dos fármacos , Proteína Quinase 1 Ativada por Mitógeno/química , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/química , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteínas do Tecido Nervoso/agonistas , Proteínas do Tecido Nervoso/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/enzimologia , Obesidade/sangue , Obesidade/induzido quimicamente , Fosforilação/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Distribuição Aleatória , Ratos Wistar , Glutamato de Sódio/toxicidadeRESUMO
Four novel unsymmetrical A3B porphyrins 1, 2, 3 and 4 were synthesized following Lindsey procedure. Porphyrins 3 and 4 include one and three l-glutamate groups, respectively, and all porphyrins were metallated with Zn(II) (1a-4a) or Cu(II) (1b-4b). Porphyrins and metalloporphyrins presented values of singlet oxygen quantum yields (ΦD) ranging from 0.21 to 0.67. The tetraaryl derivatives in this study showed phototoxicity in SiHa cells with IC50 values ranging from <0.01 to 6.56±0.11µM, the metalloporphyrin 4a showed the lowest IC50 value. Comparing the phototoxic activity between all porphyrins, functionalization of porphyrins with glutamate increased 100 times phototoxic activity (1 (IC50 4.81±0.34µM) vs. 3 (IC50 0.04±0.02µM) and 2 (IC50 5.19±0.42µM) vs. 4 (IC50 0.05±0.01µM)). This increased activity could be attributed to reduced hydrophobicity and increased ΦΔ, given by functionalization with l-glutamate. Metalloporphyrins 3a (IC50 0.04±0.01µM) and 4a (IC50<0.01µM) presented the best values ââof phototoxic activity. Therefore, functionalization and zinc metalation increased the phototoxic activity. SiHa cells treated with porphyrins 3, 4, 3a and 4a at a final concentration of 10µM, showed increased activity of caspase-3 enzyme compared to the negative control; indicating the induction of apoptosis. Differential gene expression pattern in SiHa cells was determined; treatments with metalloporphyrins 4a and 4b were performed, respectively, comparing the expression with untreated control. Treatments in both cases showed similar gene expression pattern in upregulated genes, since they share about 25 biological pathways and a large number of genes. According to the new photophysical properties related to the structural improvement and phototoxic activity, these molecules may have the potential application as photosensitizers in the photodynamic therapy.
Assuntos
Complexos de Coordenação/síntese química , Cobre/farmacologia , Ácido Glutâmico/química , Metaloporfirinas/farmacologia , Fotoquimioterapia , Zinco/farmacologia , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Linhagem Celular Tumoral , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Luz , Metaloporfirinas/síntese química , Metaloporfirinas/química , Oxigênio Singlete/análise , Regulação para Cima/efeitos dos fármacosRESUMO
Obesity and metabolic syndrome are the common causes of reproductive and fertility disorders in women. In particular, polycystic ovary syndrome, which is clinically characterized by hyperandrogenism, oligo/anovulation, and polycystic ovarian morphology, has been increasingly associated with metabolic disorders. However, given the broad interplay between metabolic and reproductive functions, this remains a field of intense research. In this study, we investigated the effect of monosodium l-glutamate (MSG)-induced obesity on reproductive biology of female rats. Newborn female rats were subcutaneously injected with MSG (4g/kg/day) or equiosmolar saline (CTR) each 2 days up to postnatal day (pnd) 10. On pnd 60, estrous cycle was evaluated using vaginal smears twice a day for 15 days, which showed MSG rats to be oligocyclic. Thereafter, animals were killed on estrous phase for blood and tissue collection. MSG rats had increased body mass, accumulation of retroperitoneal and visceral fat pads, and visceral adipocyte hypertrophy compared with CTR rats. MSG rats were also dyslipidemic and hyperinsulinemic but were normoglycemic and normoandrogenic. Ovarian morphology analysis showed that MSG rats had a two-fold decrease in oocyte count but a six-fold increase on ovarian follicular cysts, along with a higher number of total primordial and atretic follicles. Moreover, MSG rats had a four-fold increase in anti-Müllerian hormone immunohistochemical staining on antral follicles. Taken together, data presented here characterize MSG obesity as a unique model to study the metabolic pathways underlying reproductive disorders in the absence of overactivated hypothalamic-pituitary-gonadal axis.
Assuntos
Obesidade/induzido quimicamente , Obesidade/fisiopatologia , Glutamato de Sódio/toxicidade , Androgênios/metabolismo , Animais , Animais Recém-Nascidos , Hormônio Antimülleriano/metabolismo , Modelos Animais de Doenças , Feminino , Hiperinsulinismo/induzido quimicamente , Hiperinsulinismo/fisiopatologia , Redes e Vias Metabólicas/efeitos dos fármacos , Síndrome Metabólica/induzido quimicamente , Síndrome Metabólica/fisiopatologia , Obesidade/patologia , Ovário/efeitos dos fármacos , Ovário/metabolismo , Ovário/patologia , Síndrome do Ovário Policístico/induzido quimicamente , Síndrome do Ovário Policístico/fisiopatologia , Ratos , Ratos Wistar , Reprodução/efeitos dos fármacosRESUMO
L-lactate is one of main byproducts excreted in to the fermentation medium. To improve L-glutamate production and reduce L-lactate accumulation, L-lactate dehydrogenase-encoding gene ldhA was knocked out from L-glutamate producing strain Corynebacterium glutamicum GDK-9, designated GDK-9ΔldhA. GDK-9ΔldhA produced approximately 10.1% more L-glutamate than the GDK-9, and yielded lower levels of such by-products as α-ketoglutarate, L-lactate and L-alanine. Since dissolved oxygen (DO) is one of main factors affecting L-lactate formation during L-glutamate fermentation, we investigated the effect of ldhA deletion from GDK-9 under different DO conditions. Under both oxygen-deficient and high oxygen conditions, L-glutamate production by GDK-9ΔldhA was not higher than that of the GDK-9. However, under micro-aerobic conditions, GDK-9ΔldhA exhibited 11.61% higher L-glutamate and 58.50% lower L-alanine production than GDK-9. Taken together, it is demonstrated that deletion of ldhA can enhance L-glutamate production and lower the unwanted by-products concentration, especially under micro-aerobic conditions.
Assuntos
Corynebacterium glutamicum/enzimologia , Corynebacterium glutamicum/metabolismo , Deleção de Genes , Ácido Glutâmico/metabolismo , L-Lactato Desidrogenase/genética , Ácido Láctico/metabolismo , Engenharia Metabólica , Corynebacterium glutamicum/genética , Oxigênio/metabolismo , Deleção de SequênciaRESUMO
L-lactate is one of main byproducts excreted in to the fermentation medium. To improve L-glutamate production and reduce L-lactate accumulation, L-lactate dehydrogenase-encoding gene ldhA was knocked out from L-glutamate producing strain Corynebacterium glutamicum GDK-9, designated GDK-9ΔldhA. GDK-9ΔldhA produced approximately 10.1% more L-glutamate than the GDK-9, and yielded lower levels of such by-products as α-ketoglutarate, L-lactate and L-alanine. Since dissolved oxygen (DO) is one of main factors affecting L-lactate formation during L-glutamate fermentation, we investigated the effect of ldhA deletion from GDK-9 under different DO conditions. Under both oxygen-deficient and high oxygen conditions, L-glutamate production by GDK-9ΔldhA was not higher than that of the GDK-9. However, under micro-aerobic conditions, GDK-9ΔldhA exhibited 11.61% higher L-glutamate and 58.50% lower L-alanine production than GDK-9. Taken together, it is demonstrated that deletion of ldhA can enhance L-glutamate production and lower the unwanted by-products concentration, especially under micro-aerobic conditions.
Assuntos
Corynebacterium glutamicum/enzimologia , Corynebacterium glutamicum/metabolismo , Deleção de Genes , Ácido Glutâmico/metabolismo , L-Lactato Desidrogenase/genética , Ácido Láctico/metabolismo , Engenharia Metabólica , Corynebacterium glutamicum/genética , Oxigênio/metabolismo , Deleção de SequênciaRESUMO
Crotoxin (Crtx), the main toxin in the venom of Crotalus durissus terrificus snake, is a heterodimer with a basic subunit, CB, and an acidic subunit, CA. CB is a phospholipase A2 that depends on CA to specifically bind to the cell membrane. This toxin acts in the central nervous system (CNS) causing chronic seizure effects and other cytotoxic effects. Here, we report its action on glutamate release in rat cerebral cortex synaptosomes. Aiming at a better understanding of the mechanism of action of Crtx, calcium channel blockers were used and internalization studies were performed in cerebellar granule neurons. Our results show that Crtx induces calcium-dependent glutamate release via N and P/Q calcium channels. In addition, the CB subunit of Crtx is shown to be internalized. This internalization does not depend on the presence of CA subunit neither on the PLA2 activity of CB. A correlation between CB internalization and glutamate release remains to be established.
Assuntos
Agonistas dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo N/metabolismo , Córtex Cerebral/efeitos dos fármacos , Venenos de Crotalídeos/química , Crotalus , Crotoxina/farmacologia , Sinaptossomos/efeitos dos fármacos , Animais , Agonistas dos Canais de Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo N/química , Sinalização do Cálcio/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/metabolismo , Venenos de Crotalídeos/enzimologia , Crotoxina/antagonistas & inibidores , Crotoxina/metabolismo , Ácido Glutâmico/metabolismo , Fosfolipases A2 do Grupo II/antagonistas & inibidores , Fosfolipases A2 do Grupo II/metabolismo , Fosfolipases A2 do Grupo II/farmacologia , Masculino , Proteínas do Tecido Nervoso/agonistas , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurotoxinas/antagonistas & inibidores , Neurotoxinas/metabolismo , Neurotoxinas/farmacologia , Subunidades Proteicas/antagonistas & inibidores , Subunidades Proteicas/metabolismo , Subunidades Proteicas/farmacologia , Transporte Proteico/efeitos dos fármacos , Ratos Wistar , Proteínas de Répteis/antagonistas & inibidores , Proteínas de Répteis/metabolismo , Proteínas de Répteis/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Sinaptossomos/metabolismoRESUMO
L-lactate is one of main byproducts excreted in to the fermentation medium. To improve L-glutamate production and reduce L-lactate accumulation, L-lactate dehydrogenase-encoding gene ldhA was knocked out from L-glutamate producing strain Corynebacterium glutamicum GDK-9, designated GDK-9ΔldhA. GDK-9ΔldhA produced approximately 10.1% more L-glutamate than the GDK-9, and yielded lower levels of such by-products as α-ketoglutarate, L-lactate and L-alanine. Since dissolved oxygen (DO) is one of main factors affecting L-lactate formation during L-glutamate fermentation, we investigated the effect of ldhA deletion from GDK-9 under different DO conditions. Under both oxygen-deficient and high oxygen conditions, L-glutamate production by GDK-9ΔldhA was not higher than that of the GDK-9. However, under micro-aerobic conditions, GDK-9ΔldhA exhibited 11.61% higher L-glutamate and 58.50% lower L-alanine production than GDK-9. Taken together, it is demonstrated that deletion of ldhA can enhance L-glutamate production and lower the unwanted by-products concentration, especially under micro-aerobic conditions.