RESUMO
Early life stress increases the risk of abnormal brain development, and it is associated with psychological disorders. Maternal separation is an established animal model of early life stress that produces changes in the development of the central nervous system. The objective of this study was to evaluate the effect of maternal separation on the rat cerebellum, both behaviourally and physiologically. We used 32 rats, males (n = 8) and females (n = 7), subjected to maternal separation for 21 days and a control group (9 males and 8 females). Spatial reference memory was assessed using the Morris water maze, and brain metabolic activity and the expression of an immediate early gene were determined, respectively, using the histochemical technique of cytochrome c oxidase and the immunocytochemistry of c-Fos. Results showed that both groups successfully performed the spatial memory task. Although there were no behavioural differences, the experimental group showed lower metabolic activity in the medial nucleus of the cerebellum, as well as fewer c-Fos-positive cells in the three deep nuclei of the cerebellum. These decreases could contribute to the emotional or behavioural impairments reported in maternal separation subjects.
Assuntos
Cerebelo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Privação Materna , Estresse Oxidativo/fisiologia , Proteínas Proto-Oncogênicas c-fos/biossíntese , Animais , Animais Recém-Nascidos , Feminino , Masculino , Aprendizagem em Labirinto/fisiologia , Proteínas Proto-Oncogênicas c-fos/genética , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
CONTEXT/OBJECTIVE: Cell lines used to study the role of the G protein-coupled receptor 30 (GPR30) or G protein-coupled estrogen receptor (GPER) as a mediator of estrogen responses have yielded conflicting results. This work identified a simple assay to predict cell line competence for pharmacological studies of GPR30. MATERIALS AND METHODS: The phosphorylation or expression levels of ERK1/2, Akt, c-Fos and eNOS were evaluated to assess GPR30 activation in response to known agonists (17ß-estradiol and G-1) in MCF-7 and T-47D breast cancer cell lines and in bovine aortic endothelial cells. GPR30 expression was analyzed by qRT-PCR and Western blot with two distinct antibodies directed at its carboxy and amino terminals. RESULTS: None of the agonists, at any of the concentrations tested, activated any of those target proteins. Additional experiments excluded the disruption of the signaling pathway, interference of phenol red in the culture medium and constitutive proteasome degradation of GPR30 as possible causes for the lack of response of the three cell lines. Analysis of receptor expression showed the absence of clearly detectable GPR30 species of 44 and 50-55 kDa previously identified in cell lines that respond to 17ß-estradiol and G-1. DISCUSSION AND CONCLUSION: Cells that do not express the 44 and 50-55 kDa species do not respond to GPR30 agonists. Thus, the presence or absence of these GPR30 species is a simple and rapid manner to determine whether a given cell line is suitable for pharmacological or molecular studies of GPR30 modulation.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Receptor alfa de Estrogênio/metabolismo , Estrogênios/metabolismo , Receptores de Estrogênio/biossíntese , Receptores Acoplados a Proteínas G/biossíntese , Animais , Aorta/citologia , Aorta/efeitos dos fármacos , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Bovinos , Ciclopentanos/administração & dosagem , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Estradiol/administração & dosagem , Receptor alfa de Estrogênio/genética , Estrogênios/agonistas , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células MCF-7 , Proteína Oncogênica v-akt/biossíntese , Fosforilação , Proteínas Proto-Oncogênicas c-fos/biossíntese , Quinolinas/administração & dosagem , Receptores de Estrogênio/genética , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais/efeitos dos fármacosRESUMO
Selective sodium glucose cotransporter-2 inhibitor (SGLT2i) treatment promotes urinary glucose excretion, thereby reducing blood glucose as well as body weight. However, only limited body weight reductions are achieved with SGLT2i treatment. Hyperphagia is reportedly one of the causes of this limited weight loss. However, the effects of SGLT2i treatment on systemic energy expenditure have not been fully elucidated. Herein, we investigated the acute effects of dapagliflozin, a SGLT2i, on systemic energy expenditure in mice. Eighteen hours after dapagliflozin treatment oxygen consumption and brown adipose tissue (BAT) expression of ucp1, a thermogenesis-related gene, were significantly decreased as compared to those after vehicle treatment. In addition, dapagliflozin significantly suppressed norepinephrine (NE) turnover in BAT and c-fos expression in the rostral raphe pallidus nucleus (rRPa) which contains the sympathetic premotor neurons responsible for thermogenesis. These findings indicate that the dapagliflozin-mediated acute decrease in energy expenditure involves a reduction in BAT thermogenesis via decreased sympathetic nerve activity from the rRPa. Furthermore, common hepatic branch vagotomy abolished the reductions in ucp1 expression and NE contents in BAT and c-fos expression in the rRPa. In addition, alterations in hepatic carbohydrate metabolism, such as decreases in glycogen contents and upregulation of phosphoenolpyruvate carboxykinase, manifested prior to the suppression of BAT thermogenesis, e.g. 6 hours after dapagliflozin treatment. Collectively, these results suggest that SGLT2i treatment acutely suppresses energy expenditure in BAT via regulation of an inter-organ neural network consisting of the common hepatic vagal branch and sympathetic nerves.
Assuntos
Tecido Adiposo Marrom/metabolismo , Compostos Benzidrílicos/farmacologia , Metabolismo Energético/efeitos dos fármacos , Glucosídeos/farmacologia , Inibidores do Transportador 2 de Sódio-Glicose , Transmissão Sináptica/efeitos dos fármacos , Termogênese/efeitos dos fármacos , Animais , Metabolismo dos Carboidratos/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Glicogênio/metabolismo , Canais Iônicos/biossíntese , Fígado/metabolismo , Masculino , Camundongos , Núcleos da Rafe do Mesencéfalo/metabolismo , Proteínas Mitocondriais/biossíntese , Proteínas Proto-Oncogênicas c-fos/biossíntese , Transportador 2 de Glucose-Sódio/metabolismo , Proteína Desacopladora 1 , Nervo Vago/metabolismoRESUMO
Desde diciembre de 2013, la Región de las Américas se enfrenta por primera vez a una epidemia de chikungunya. Los casos iniciales se registraron en el Caribe francés y, debido al comercio y la movilización de personas, esta epidemia no tardó en llegar a la República Dominicana, cuya población es de 10 millones de habitantes y comparte con Haití la isla La Española. En este artículo se difunde información extraída de diversos artículos y documentos oficiales sobre el virus, la infección y la epidemia de chikungunya, que han sido de gran ayuda para orientar la respuesta en la República Dominicana y pueden ser útiles para mejorar tanto el conocimiento como las actuaciones frente a la epidemia de los trabajadores del sector salud de la Región. Se destaca la importancia que revisten las investigaciones realizadas en países y territorios afectados del océano Índico, como la isla de Reunión, durante la epidemia declarada entre 2005 y 2007, cuando se registró una tasa de ataque mayor de 30%, se identificaron los grupos de riesgo, las formas graves y atípicas de la infección, la transmisión vertical del virus, las formas crónicas, que pueden provocar dolores recurrentes durante tres años, y las defunciones directa o indirectamente relacionadas con el virus chikungunya. Por su alta tasa de ataque, el virus chikungunya se convierte en un reto sin precedentes para los ministerios de salud, que exige una adecuada organización de los servicios de salud, la priorización de la atención a los grupos de riesgo y a los pacientes con formas graves de la enfermedad, así como una adecuada comunicación social y respuesta intersectorial.
The Region of the Americas has been affected since December 2013 by a chikungunya epidemic for the first time. Although the first cases were recorded in the French Caribbean, the epidemic quickly spread to the Dominican Republic due to trade and people movements. The Dominican Republic, which shares the island of Hispaniola with Haiti, has a population of 10 million. This article contains information from a range of different publications and official documents about the chikungunya virus infection and epidemic. These papers were extremely helpful for guiding the response to the epidemic in the Dominican Republic and may also be useful for enhancing knowledge of the virus and responses among health workers elsewhere in the region. Particular attention is drawn to the important research undertaken in countries and territories affected by the epidemic in the Indian Ocean area. This is the case, for example, of the island of La Réunion, where the epidemic had an attack rate of more than 30% between 2005 and 2007. Researchers were able to identify risk groups, severe and atypical forms of the infection, cases of vertical transmission, chronic disease causing recurrent pain over three years, and directly- or indirectly-related deaths from the virus. Given its high attack rate, the chikungunya virus has emerged as an exceptional challenge for health ministries and calls for appropriate organized responses from the health services, prioritization of care for risk groups and patients exhibiting severe forms of the disease, and effective social communication and intersectoral actions.
Assuntos
Animais , Ratos , DNA , Angiotensina II/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , /análogos & derivados , Vasoconstritores/farmacologia , Anti-Hipertensivos/farmacologia , Benzimidazóis/farmacologia , Compostos de Bifenilo/farmacologia , Divisão Celular/fisiologia , Células Cultivadas , Músculo Liso Vascular/fisiologia , Proteínas Proto-Oncogênicas c-fos/biossíntese , RNA Mensageiro/metabolismo , Ratos Endogâmicos WKY , Tetrazóis/farmacologia , /farmacologiaRESUMO
We have previously reported that a mild maternal hyperthyroidism in rats impairs stress coping of adult offspring. To assess anxiogenesis in this rat model of stress over-reactivity, we used two behavioural tests for unconditional and conditional anxious states: elevated plus maze test (EPM) and Vogel conflict test (VCT). In the latter one, arginine vasopressin (AVP) release was enhanced due to osmotic stress. With the EPM test no differences were observed between maternal hyperthyroid rats (MH) and controls. However, with the VCT, the MH showed increased anxiety-like behaviour. This behavioural difference was abolished by diazepam. Plasma AVP concentration curve as a function of water deprivation (WD) time showed a marked increase, reaching its maximal levels within half the time of controls and another significant difference after VCT. A general increase in Fos expression in hypothalamic supraoptic and paraventricular nuclei (PVN) was observed during WD and after VCT. There was also a significant increase of AVP immunoreactivity in anterior hypothalamic area. A large number of Herring bodies were observed in the AVP containing fibres of MH hypothalamic-neurohypophysial system. Numerous reciprocal synaptic connections between AVP and corticotropin releasing factor containing neurons in MH ventromedial PVN were observed by electron microscopy. These results suggest that a mild maternal hyperthyroidism could induce an aberrant organization in offspring's hypothalamic stress related regions which could mediate the enhanced anxiety seen in this animal model.
Assuntos
Ansiedade/metabolismo , Ansiedade/psicologia , Arginina Vasopressina/sangue , Hipertireoidismo/complicações , Neurônios/fisiologia , Complicações na Gravidez , Proteínas Proto-Oncogênicas c-fos/biossíntese , Animais , Ansiedade/etiologia , Conflito Psicológico , Hormônio Liberador da Corticotropina/metabolismo , Feminino , Aprendizagem em Labirinto , Osmose , Núcleo Hipotalâmico Paraventricular/metabolismo , Gravidez , Terminações Pré-Sinápticas/fisiologia , Ratos , Ratos Wistar , Estresse Fisiológico , Núcleo Supraóptico/metabolismo , Sinapses/fisiologia , Privação de ÁguaRESUMO
Lipopolysaccharide (LPS) is often used to mimic acute infection and induces hypophagia, the selective partitioning of fat for energy, and fever. Interleukin-10 (IL-10) is an anti-inflammatory cytokine expressed in the brain which attenuates LPS-induced hypophagia; however the potential sites of interaction within the brain have not been investigated. Hypothalamic orexin (ORX) and melanin-concentrating hormone (MCH) regulate energy expenditure and food intake although the regulation of these neuropeptides through the interactions between central IL-10 and the inflammatory consequences of peripheral LPS have not been investigated. The present study in the rat investigated during the dark phase of the light-dark cycle the ability of central IL-10 (250 ng, i.c.v.) to attenuate the changes in food intake, energy substrate partitioning, and central Fos expression within the hypothalamus to peripheral LPS (100 microg/kg, i.p.); Fos expression changes specifically within ORX and MCH neurons were also investigated. Central IL-10 attenuated the peripheral LPS-induced hypophagia, reduction in motor activity, fever and reduction in respiratory exchange ratio. Central IL-10 also attenuated peripheral LPS-induced increases in Fos expression within ORX neurons and decreases in Fos expression within unidentified cells of the caudal arcuate nucleus. In contrast, both IL-10 and LPS injection independently decreased Fos expression within MCH neurons. The present study provides further insight into the interactions within the brain between the anti-inflammatory cytokine IL-10, the inflammatory consequences of LPS, and neuropeptides known to regulate energy expenditure and food intake.
Assuntos
Ingestão de Alimentos/fisiologia , Metabolismo Energético/fisiologia , Hipotálamo/metabolismo , Interleucina-10/administração & dosagem , Lipopolissacarídeos/antagonistas & inibidores , Lipopolissacarídeos/toxicidade , Proteínas Proto-Oncogênicas c-fos/biossíntese , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/antagonistas & inibidores , Anti-Inflamatórios não Esteroides/metabolismo , Anti-Inflamatórios não Esteroides/toxicidade , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Hipotálamo/efeitos dos fármacos , Mediadores da Inflamação/administração & dosagem , Mediadores da Inflamação/antagonistas & inibidores , Mediadores da Inflamação/metabolismo , Mediadores da Inflamação/toxicidade , Injeções Intraventriculares , Masculino , Neuropeptídeos/fisiologia , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/administração & dosagemRESUMO
Induction of Fos protein by the potent and direct NMDA agonist (tetrazol-5-yl)glycine (TZG) was examined in mice. Effects of antipsychotic drugs were assessed on this in vivo index of NMDA receptor activation. TZG induced the expression of Fos in a neuroanatomically selective manner, with the hippocampal formation showing the most robust response. In mice genetically altered to express low levels of the NR1 subunit of the NMDA receptor, TZG-induced Fos was reduced markedly in comparison to the wild type controls. TZG-induced Fos was also blocked by the selective NMDA antagonist MK-801. Pretreatment of mice with clozapine (3 and 10 mg/kg) reduced TZG-induced Fos in the hippocampal formation but not in other brain regions. Haloperidol at a dose of 0.5 mg/kg did not antagonize TZG induced Fos in any region. Haloperidol at a dose of 1.0 mg/kg did attenuate the induction of Fos by TZG in the hippocampus but not in other brain regions. The relatively high dose (1 mg/kg) of haloperidol required to block effects of TZG suggests that this action may not be related to the D(2) dopamine receptor-blocking properties, since maximal D(2) receptor blockade was probably achieved by the 0.5 mg/kg dose of haloperidol. The antidepressant drug imipramine (10 or 20 mg/kg) did not antagonize TZG induced Fos in any brain region. The data suggest that clozapine can reduce excessive activation of NMDA receptors by TZG administration in vivo at doses relevant to the drugs' actions in rodent models of antipsychotic activity. Whether or not this action of clozapine contributes to its therapeutic properties will require further study.
Assuntos
Clozapina/farmacologia , Glicina/análogos & derivados , Haloperidol/farmacologia , N-Metilaspartato/agonistas , Proteínas Proto-Oncogênicas c-fos/biossíntese , Receptores de N-Metil-D-Aspartato/metabolismo , Tetrazóis/farmacologia , Animais , Glicina/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Camundongos Transgênicos , Proteínas Proto-Oncogênicas c-fos/genética , Receptores de Glutamato Metabotrópico/deficiência , Receptores de Glutamato Metabotrópico/genéticaRESUMO
Factors predicting sensitivity to epidermal growth factor receptor (EGFR) blockade are largely unknown and new strategies are being sought to individualize cancer therapy. This study evaluated the variation in the expression of the early response gene c-fos as a distal effect of EGFR inhibition and its relationship to antitumor effects. The growth-inhibitory and c-fos-modulating effects of gefitinib and erlotinib in human cancer cell lines (A431, CAL27, HN11, HuCCT1, and Hep2) were determined. Next, these cell lines were xenografted in mice and treated for 14 days with gefitinib (A431 and HuCCT1) or erlotinib (CAL27, HN11, and Hep2). Fine needle aspiration biopsy of tumors was done at baseline and after 14 days of therapy for c-fos assessment. In addition, we tested the feasibility of analyzing this marker in five paired tumor samples from a clinical trial of gefitinib in patients with solid tumors. In culture, gefitinib and erlotinib decreased c-fos mRNA levels in the susceptible cell lines A431, CAL27, and HN11; however, both drugs failed to achieve c-fos inhibition in resistant cells. Gefitinib or erlotinib abrogated the increase in c-fos expression in vivo in EGFR-sensitive A431, CAL27, and HN11 tumors but not in resistant strains. Ex vivo evaluation was feasible and predicted in vivo effects. The feasibility study in paired human tumor biopsies showed that this biomarker can be reliably measured in clinical materials. In summary, variations in c-fos expression reflect the pharmacologic actions of EGFR inhibitors in in vitro and in vivo models.
Assuntos
Biomarcadores Tumorais/análise , Receptores ErbB/antagonistas & inibidores , Genes fos/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-fos/genética , RNA Mensageiro/análise , Animais , Biomarcadores Tumorais/biossíntese , Biomarcadores Tumorais/genética , Processos de Crescimento Celular/efeitos dos fármacos , Processos de Crescimento Celular/genética , Linhagem Celular Tumoral , Fator de Crescimento Epidérmico/farmacologia , Cloridrato de Erlotinib , Feminino , Gefitinibe , Humanos , Camundongos , Camundongos Nus , Neoplasias/tratamento farmacológico , Neoplasias/genética , Proteínas Proto-Oncogênicas c-fos/biossíntese , Quinazolinas/farmacologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
UNLABELLED: Some oral cancers are known to develop from dysplastic oral epithelium. In the present study, the expression of c-Jun, c-Fos, and cyclin D1 proteins in oral epithelial lesions with different degrees of dysplasia, and in oral squamous cell carcinomas (OSCCs) was evaluated. Eighteen cases of mild dysplasia, 23 cases of moderate to severe dysplasia and 24 OSCCs were studied immunohistochemically. Additionally, 15 sections of oral mucosa without any evidence of dysplasia were included in the study. RESULTS: c-Jun expression increased according to the degree of oral dysplasia, with the greatest expression found in OSCC. c-Fos expression was intense in normal mucosa, reduced in mild dysplasia and high in moderate to severe dysplasia and in OSCCs. Cyclin D1 was expressed in only a few cases of moderate to severe dysplasia and in most of the OSCCs. Statistical analysis showed a correlation between the three proteins and the degree of epithelial alteration. The present results indicate a possible role of c-Jun and c-Fos in malignant transformation of oral mucosa.
Assuntos
Carcinoma de Células Escamosas/metabolismo , Transformação Celular Neoplásica/metabolismo , Leucoplasia Oral/metabolismo , Proteínas Proto-Oncogênicas/biossíntese , Neoplasias da Língua/metabolismo , Biomarcadores Tumorais/análise , Biomarcadores Tumorais/biossíntese , Carcinoma de Células Escamosas/química , Transformação Celular Neoplásica/química , Ciclina D1/análise , Ciclina D1/biossíntese , Humanos , Imuno-Histoquímica , Leucoplasia Oral/química , Mucosa Bucal/química , Mucosa Bucal/metabolismo , Proteínas Proto-Oncogênicas/análise , Proteínas Proto-Oncogênicas c-fos/análise , Proteínas Proto-Oncogênicas c-fos/biossíntese , Proteínas Proto-Oncogênicas c-jun/análise , Proteínas Proto-Oncogênicas c-jun/biossíntese , Neoplasias da Língua/química , Fator de Transcrição AP-1/metabolismoRESUMO
Like leptin (OB protein), central infusion of the nonspecific melanocortin agonist MTII reduces food intake for relatively long periods of time (i.e., 12 h; W. Fan, B. A. Boston, R. A. Kesterson, V. J. Hruby, and R. D. Cone, Nature; 385: 165-168, 1997). To test the hypothesis that MTII may influence ingestive behavior via mechanisms similar to those that mediate the effects of leptin, we infused a single dose of MTII into the third ventricle (i3vt) of Long-Evans rats and examined three dependent measures that have been studied following i3vt infusion of leptin: 1) effects on long-term food intake and body weight (48 h), 2) patterns of c-Fos expression in the brain, and 3) conditioned taste aversion learning. Similar to leptin, MTII reduced 48-h food intake (1.0 nmol dose), reduced body weight at 24 and 48 h (0.1 and 1.0 nmol doses, respectively), and induced c-Fos expression in the paraventricular nucleus of the hypothalamus and the central nucleus of the amygdala. In contrast to leptin, MTII was found to produce conditioned taste aversions. These results are consistent with the hypothesis that MTII may influence regulatory behavior via mechanisms similar to those that mediate the effects of leptin.
Assuntos
Tonsila do Cerebelo/fisiologia , Aprendizagem da Esquiva/efeitos dos fármacos , Ventrículos Cerebrais/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Hormônios Estimuladores de Melanócitos/agonistas , Núcleo Hipotalâmico Paraventricular/fisiologia , Proteínas/farmacologia , Proteínas Proto-Oncogênicas c-fos/biossíntese , Paladar , alfa-MSH/análogos & derivados , Administração Oral , Tonsila do Cerebelo/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Ventrículos Cerebrais/efeitos dos fármacos , Infusões Parenterais , Leptina , Masculino , Obesidade , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Proteínas/administração & dosagem , Ratos , Sacarina/administração & dosagem , Sacarina/farmacologia , alfa-MSH/farmacologiaRESUMO
We investigated descending projections from the secondary somatosensory cortex to the feline spinal cord and the effects of long-lasting potentiation in secondary somatosensory cortex on the activities of motoneurons of the cat. Electrophysiological examinations revealed that the low-intensity subthreshold secondary somatosensory cortex stimulation could change the H-Reflex induced by radial nerve stimulation. The H-wave amplitudes, recorded in wrist flexor muscles, were enhanced when the intervals from secondary somatosensory cortex to radial nerve stimuli were altered from 0 to 30 ms (initial excitation, 146 +/- 11% (mean +/- S.E.M.) of the control value). In contrast, the H-waves were suppressed with intervals longer than 30 ms (80 +/- 3%). The descending pathways from secondary somatosensory cortex to the spinal cord were assessed using an immunohistochemical technique. c-Fos and Zif268 proteins, induced by stimulation of the hand-represented secondary somatosensory cortex areas, could thus express in activated cervical neurons. The density of labeled cells was significantly higher in the seventh and eighth cervical segments than in other levels. The great majority of positive cells were distributed in the lateral part of the contralateral ventral horn and their somas ranged from 10 to 50 microns in size. Finally, we examined the effects of long-lasting potentiation, induced by high-frequency stimulation of the ventral posterolateral thalamic nucleus, on the activities of spinal motoneurons. Long-lasting potentiation altered the previously observed effects of secondary somatosensory cortex stimulation on the H-wave amplitude. The secondary somatosensory cortex-conditioned initial excitation of the H-reflex was enhanced (from 139 to 175%, P < 0.05), while late suppression was completely blocked (from 74 to 112%, P < 0.01). In conclusion, the descending pathways from secondary somatosensory cortex to the spinal cord modulated the H-reflex, and long-lasting potentiation in secondary somatosensory cortex affected this modulation. We have previously reported that corticocortical inputs from primary to secondary somatosensory cortex is required for induction of long-lasting potentiation in secondary somatosensory cortex. Taken together, the present study suggests that cortical plasticity in secondary somatosensory cortex amplifies somatic inputs from primary somatosensory cortex as a means of adaptive motor control by the sensory system.
Assuntos
Reflexo H/fisiologia , Potenciação de Longa Duração/fisiologia , Neurônios Motores/fisiologia , Córtex Somatossensorial/fisiologia , Medula Espinal/fisiologia , Animais , Mapeamento Encefálico , Gatos , Proteínas de Ligação a DNA/biossíntese , Estimulação Elétrica , Eletromiografia , Eletrofisiologia , Imuno-Histoquímica , Vias Neurais/citologia , Vias Neurais/fisiologia , Proteínas Proto-Oncogênicas c-fos/biossíntese , Córtex Somatossensorial/citologia , Córtex Somatossensorial/metabolismo , Medula Espinal/citologia , Medula Espinal/metabolismo , Fatores de Transcrição/biossínteseRESUMO
Immediate early genes are rapidly and transiently induced by many stimuli and produce their transcription factors. Of the immediate early genes, the proto-oncogene c-fos and its product Fos play a role in cell proliferation, differentiation and general signal transmission as the 'third messenger' regulating the transcription of other genes. Even minute stimuli such as the attachment of electrodes, needle injection and saline administration increase the level of c-fos mRNA expression in animal brains. It is, therefore, necessary to investigate the effects of using anesthetics and solvents for drug administration on c-fos expression in order to accurately assess net c-fos induction after stimulation. Furthermore, experimental procedures might themselves affect c-fos mRNA expression in the brain after in vivo stimulation. In this review, we discuss technical pitfalls in assessing in vivo c-fos expression. Rough handling with repeated saline administration enhanced cortical c-fos mRNA expression in the rat brain after a single saline injection by increasing baseline c-fos mRNA levels. In contrast, gentle handling with repeated saline administration diminished c-fos mRNA expression after a single injection by decreasing baseline c-fos mRNA levels. These two types of handling with the repeated injection led to diametrically opposite results on c-fos mRNA expression after a single stimulation. Our results suggest that c-fos mRNA induction after a single stimulation might be affected by the types or intensities of animal handling and that effects of animal handling must be considered when estimating c-fos mRNA induction.
Assuntos
Química Encefálica/fisiologia , Expressão Gênica/fisiologia , Manobra Psicológica , Proteínas Proto-Oncogênicas c-fos/biossíntese , RNA Mensageiro/biossíntese , Animais , Química Encefálica/genética , Proteínas Proto-Oncogênicas c-fos/genéticaRESUMO
Alterations in brain activity patterns were assessed in response to swim stress by immunocytochemical detection of Fos-like immunoreactivity (Fos-LI) and high-resolution autoradiographic imaging of 14C-2-deoxyglucose (2-DG) uptake. The stress paradigm investigated was a classic behavioral screen for antidepressant drug activity, the forced swim test. One of the most pronounced effects produced by swim stress was an increase in 2-DG uptake and induction of Fos-LI in a restricted region of the lateral septal nucleus. Specific "limbic" cortical regions, including the medial prefrontal, ventrolateral orbital, and cingulate cortices, also exhibited both increased 2-DG uptake and expression of Fos-LI in response to swim stress. In the hypothalamic paraventricular nucleus of swim-stressed rats, Fos-LI was induced but no change in 2-DG uptake was apparent. Since the specific swim stress protocol used is a behavioral screen for antidepressant drugs, the effects of imipramine on stress-induced alterations in 2-DG uptake and induction of Fos-LI were examined. The stress-induced increase in 2-DG uptake in the lateral septum was blocked by treatment with imipramine, but treatment with imipramine had no effect on induction of Fos-LI in the same region. Neither 2-DG uptake nor Fos-LI expression was altered by imipramine treatment in the cortical regions influenced by swim stress. Administration of imipramine alone under basal conditions produced a robust induction of Fos-LI in the central nucleus of the amygdala and in the dorsal lateral subdivision of the bed nucleus of the stria terminalis. No effect of imipramine treatment on 2-DG uptake was apparent in these latter regions. The results provide insights into topographic patterns of brain activity associated with swim stress and neuroanatomically selective actions of imipramine. The different and complementary information obtained by assessment of Fos-LI and 2-DG uptake illustrates the utility of applying both functional mapping approaches to examine neuroanatomical correlates of behavioral states and drug treatment.