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BACKGROUND: Metastatic clear cell renal cell carcinoma (ccRCC) patients have <9% 5-year survival rate, do not respond well to targeted therapy and eventually develop resistance. A better understanding of molecular pathways of RCC metastasis is the basis for the discovery of novel prognostic markers and targeted therapies. METHODS: We investigated the biological impact of galectin-1 (Gal-1) in RCC cell lines by migration and invasion assays. Effect of Gal-1 expression on the mitogen-activated protein kinase pathway was assessed by proteome array. RESULTS: Increased expression of Gal-1 increased cell migration while knocking down Gal-1 expression by siRNA resulted in reduced cellular migration (P<0.001) and invasion (P<0.05). Gal-1 overexpression increased phosphorylation of Akt, mTOR and p70 kinase. Upon hypoxia and increased HIF-1α, Gal-1 increased in a dose-dependent manner. We also found miR-22 overexpression resulted in decreased Gal-1 and HIF-1α. Immunohistochemistry analysis showed that high Gal-1 protein expression was associated with larger size tumor (P=0.034), grades III/IV tumors (P<0.001) and shorter disease-free survival (P=0.0013). Using the Cancer Genome Atlas data set, we found that high Gal-1 mRNA expression was associated with shorter overall survival (41 vs 78 months; P<0.01). CONCLUSIONS: Our data suggest Gal-1 mediates migration and invasion through the HIF-1α-mTOR signaling axis and is a potential prognostic marker and therapeutic target.
Assuntos
Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Galectina 1/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Serina-Treonina Quinases TOR/metabolismo , Carcinoma de Células Renais/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Progressão da Doença , Intervalo Livre de Doença , Galectina 1/genética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Neoplasias Renais/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação , Prognóstico , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/genéticaRESUMO
BACKGROUND: Renal cell carcinoma (RCC) is the most common neoplasm of the adult kidney. Metastatic RCC is difficult to treat. The 5-year survival rate for metastatic RCC is ≤10%. Recently, microRNAs (miRNAs) have been shown to have a role in cancer metastasis and potential as prognostic biomarkers in cancer. METHOD: We performed a miRNA microarray to identify a miRNA signature characteristic of metastatic compared with primary RCCs. We validated our results by quantitative real-time PCR. We performed experimental and bioinformatic analyses to explore the involvement of miR-215 in RCC progression and metastasis. RESULTS: We identified 65 miRNAs that were significantly altered in metastatic compared with primary RCCs. We validated our results by examining the expression of miR-10b, miR-126, miR-196a, miR-204 and miR-215, in two independent cohorts of patients. We showed that overexpression of miR-215 decreased cellular migration and invasion in an RCC cell line model. In addition, through gene expression profiling, we identified direct and indirect targets of miR-215 that can contribute to tumour metastasis. CONCLUSION: Our analysis showed that miRNAs are altered in metastatic RCCs and can contribute to kidney cancer metastasis through different biological processes. Dysregulated miRNAs represent potential prognostic biomarkers and may have therapeutic applications in kidney cancer.
Assuntos
Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Genes Supressores de Tumor , Neoplasias Renais/genética , Neoplasias Renais/patologia , MicroRNAs/genética , Biomarcadores Tumorais/genética , Carcinoma de Células Renais/metabolismo , Processos de Crescimento Celular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Progressão da Doença , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Testes Genéticos/métodos , Proteínas de Homeodomínio/metabolismo , Humanos , Neoplasias Renais/metabolismo , Análise em Microsséries/métodos , Invasividade Neoplásica , Metástase Neoplásica , Proteínas do Tecido Nervoso/metabolismo , Prognóstico , Proteínas de Ligação a RNA/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/métodos , Proteínas Repressoras/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Taxa de Sobrevida , Homeobox 2 de Ligação a E-box com Dedos de ZincoRESUMO
Short-term reattendances to emergency departments are a key quality of care indicator. Identifying patients at increased risk of early reattendance could help reduce the number of missed critical illnesses and could reduce avoidable utilization of emergency departments by enabling targeted post-discharge intervention. In this manuscript, we present a retrospective, single-centre study where we created and evaluated an extreme gradient boosting decision tree model trained to identify patients at risk of reattendance within 72 h of discharge from an emergency department (University Hospitals Southampton Foundation Trust, UK). Our model was trained using 35,447 attendances by 28,945 patients and evaluated on a hold-out test set featuring 8847 attendances by 7237 patients. The set of attendances from a given patient appeared exclusively in either the training or the test set. Our model was trained using both visit level variables (e.g., vital signs, arrival mode, and chief complaint) and a set of variables available in a patients electronic patient record, such as age and any recorded medical conditions. On the hold-out test set, our highest performing model obtained an AUROC of 0.747 (95% CI 0.722-0.773) and an average precision of 0.233 (95% CI 0.194-0.277). These results demonstrate that machine-learning models can be used to classify patients, with moderate performance, into low and high-risk groups for reattendance. We explained our models predictions using SHAP values, a concept developed from coalitional game theory, capable of explaining predictions at an attendance level. We demonstrated how clustering techniques (the UMAP algorithm) can be used to investigate the different sub-groups of explanations present in our patient cohort.
Assuntos
Algoritmos , Estado Terminal/terapia , Serviço Hospitalar de Emergência/organização & administração , Hospitalização/estatística & dados numéricos , Aprendizado de Máquina , Alta do Paciente/estatística & dados numéricos , Readmissão do Paciente/estatística & dados numéricos , Adolescente , Adulto , Assistência ao Convalescente/estatística & dados numéricos , Idoso , Registros Eletrônicos de Saúde , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Triagem , Adulto JovemRESUMO
BACKGROUND: Kallikrein-related peptidases (KLKs) are a family of serine proteases that have been shown to be dysregulated in several malignancies including ovarian cancer. The control of kallikrein genes and their physiological function in cancer is not well understood. We hypothesized that microRNAs (miRNAs) represent a novel mechanism for post-transcriptional control of KLK expression in cancer. METHODS: We first analysed miRNA expression in ovarian cancer in silico. A total of 98 miRNAs were reported to have altered expression in ovarian cancer. Three of these miRNAs were predicted to target KLK10. We experimentally verified the predicted miR-KLK10 interaction using two independent techniques, a luciferase assay with a construct containing the KLK10 3' untranslated region (UTR), pMIR-KLK10, and measuring KLK10 protein levels after transfection with miRNA. RESULTS: When we co-transfected cells with pMIR-KLK10 and either let-7f, miR-224, or mR-516a, we saw decreased luciferase signal, suggesting that these miRNAs can target KLK10. We then examined the effect of these three miRNAs on KLK10 protein expression and cell growth. Transfection of all miRNAs, let-7f, miR-224, and miR-516a led to a decrease in protein expression and cellular growth. This effect was shown to be dose dependent. The KLK10 protein levels were partially restored by co-transfecting let-7f and its inhibitor. In addition, there was a slight decrease in KLK10 mRNA expression after transfection with let-7f. CONCLUSION: Our results confirm that KLKs can be targeted by more than one miRNA. Increased expression of certain miRNAs in ovarian cancer can lead to decreased KLK protein expression and subsequently have a negative effect on cell proliferation. This dose-dependent effect suggests that a 'tweaking' or 'fine-tuning' mechanism exists in which the expression of one KLK can be controlled by multiple miRNAs. These data together suggest that miRNA may be used as potential therapeutic options and further studies are required.
Assuntos
Regulação Neoplásica da Expressão Gênica , Calicreínas/metabolismo , MicroRNAs/fisiologia , Sequência de Bases , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Humanos , Dados de Sequência Molecular , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Filogenia , TransfecçãoRESUMO
BACKGROUND: The human kallikrein-related peptidase family consists of 15 genes. Twelve of these genes are overexpressed in ovarian cancer and may represent potential markers for diagnosis, prognosis, and/or response to treatment. The aim of this study was to determine the prognostic significance of kallikrein-related peptidase 6 (KLK6) and kallikrein-related peptidase 13 (KLK13) in epithelial ovarian cancer by quantifying gene expression levels with tumour pathology and patient survival data. METHODS: Total RNA was isolated from 106 patients diagnosed with primary ovarian cancer, as well as 8 normal ovary controls. Samples were analysed by quantitative real-time PCR for KLK6 and KLK13 expression. Correlation between kallikrein gene expression and clinical characteristics was evaluated with the chi(2)-test. Survival analysis was performed using Kaplan-Meier and Cox proportional hazards regression models. RESULTS: Expression levels of both KLK6 and KLK13 mRNA were significantly increased in invasive cancers relative to normal ovaries (P=0.002 and 0.039 respectively). High KLK6 and KLK13 expression was an indicator of poor prognosis, with patients having a shorter recurrence-free survival (P=0.002 and 0.027 respectively). High KLK6 expression was also significantly associated with lower overall survival (P=0.011). When subjected to multivariate analysis, patients with either high KLK6 or KLK13 were 3- and 2.2-fold, respectively, more likely to have a recurrence than patients with low kallikrein expression. CONCLUSION: These data show increased mRNA expression of KLK6 and KLK13 in ovarian cancer compared to normal ovarian tissues. High KLK6 or KLK13 expression in primary ovarian tumours can significantly predict prognosis in terms of recurrence-free survival and overall survival. In all, this study shows KLK6 and KLK13 as potential biomarkers and may be therapeutic targets for treatment of ovarian cancer.
Assuntos
Calicreínas/genética , Neoplasias Epiteliais e Glandulares/mortalidade , Neoplasias Ovarianas/mortalidade , Feminino , Humanos , Imuno-Histoquímica , Calicreínas/análise , Recidiva Local de Neoplasia , Neoplasias Epiteliais e Glandulares/química , Neoplasias Epiteliais e Glandulares/metabolismo , Neoplasias Ovarianas/química , Neoplasias Ovarianas/metabolismo , Prognóstico , RNA Mensageiro/análise , Análise de RegressãoRESUMO
The dopamine D3 receptor is expressed primarily in regions of the brain that are thought to influence motivation and motor functions. To specify in vivo D3 receptor function, we generated mutant mice lacking this receptor. Our analysis indicates that in a novel environment, D3 mutant mice are transiently more active than wild-type mice, an effect not associated with anxiety state. Moreover, D3 mutant mice exhibit enhanced behavioral sensitivity to combined injections of D1 and D2 class receptor agonists, cocaine and amphetamine. However, the combined electrophysiological effects of the same D1 and D2 agonists on single neurons within the nucleus accumbens were not altered by the D3 receptor mutation. We conclude that one function of the D3 receptor is to modulate behaviors by inhibiting the cooperative effects of postsynaptic D1 and other D2 class receptors at systems level.
Assuntos
Agonistas de Dopamina/farmacologia , Atividade Motora/fisiologia , Neurônios/fisiologia , Núcleo Accumbens/fisiologia , Receptores de Dopamina D1/fisiologia , Receptores de Dopamina D2/fisiologia , Anfetamina/farmacologia , Animais , Ansiedade , Quimera , Cocaína/farmacologia , Condicionamento Operante , Cruzamentos Genéticos , Sinais (Psicologia) , Eletrofisiologia/métodos , Feminino , Habituação Psicofisiológica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Atividade Motora/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Núcleo Accumbens/efeitos dos fármacos , Reação em Cadeia da Polimerase , Receptores de Dopamina D2/deficiência , Receptores de Dopamina D2/genética , Receptores de Dopamina D3RESUMO
Runoff from two similar drainage areas in the Piedmont physiographic region of North Carolina was monitored simultaneously for 5.6 years. One of the drainage areas was developed as part of a large residential subdivision, while the other remained in woods and agricultural fields. Runoff volume was 68% greater for the developed compared with the undeveloped area, and baseflow as a percentage of overall discharge was approximately 0% compared with 25% for the undeveloped area. Overall annual export of sediment was 95% greater for the developed area, while export of nitrogen and phosphorus forms was 66 to 88% greater for the developed area. These results document the significant increases in runoff, sediment, and nutrient export associated with residential development.
Assuntos
Urbanização , Movimentos da Água , Poluentes Químicos da Água/análise , Agricultura , Amônia/análise , Monitoramento Ambiental , Sedimentos Geológicos , Habitação , Nitratos/análise , Nitrogênio/análise , North Carolina , Fósforo/análise , Chuva , ÁrvoresRESUMO
Well-ordered and highly interconnected 3D semiconducting nanostructures of bismuth sulphide were prepared from inverse cubic lipid mesophases. This route offers significant advantages in terms of mild conditions, ease of use and electrode architecture over other routes to nanomaterials synthesis for device applications. The resulting 3D bicontinous nanowire network films exhibited a single diamond topology of symmetry Fd3m (Q227) which was verified by Small angle X-ray scattering (SAXS) and Transmission electron microscopy (TEM) and holds great promise for potential applications in optoelectronics, photovoltaics and thermoelectrics.
RESUMO
A synthesis of older and recent work on mnemonic functions of the basal ganglia in rats, monkeys and humans emphasizes a reciprocal relationship of the caudate nucleus and putamen with the cerebral cortex, which mediates the memory of consistent relationships between stimuli and responses (sometimes called habits) that often involve relationships between the individual and its environment (egocentric memory). Evidence at several levels of analysis (including neuroplastic synaptic changes, activity of single neurons, and behavioral changes caused by lesions or neurochemical manipulations) implicate dopamine release from nigro-striatal neurons in the reinforcement, or strengthening, of neural representations in the basal ganglia.
Assuntos
Gânglios da Base/fisiologia , Memória/fisiologia , Animais , RatosRESUMO
Research with animals suggests that structures within the amygdaloid nuclear complex (ANC) are critical for acquiring associations between rewarding events and neutral stimuli, a form of conditioning often manifested in a subsequent preference for those (conditioned) stimuli. In this study, we investigated the relationship between the ANC and preference learning in humans. Three abstract monochrome patterns were presented to each subject over 180 trials in the context of a counting task requiring working memory. One pattern was paired with food reward on 90% of the trials in which it was presented and with no food reward on the other 10% of trials. The other patterns were similarly reinforced, but at ratios of 50:50% and 10:90% with reward and nonreward, respectively. Subsequently, a group of 21 normal participants preferred the pattern paired most often with reward to that paired least often with reward, and they did not explicitly relate their preferences to the conditioning procedure, but instead attributed them to the characteristics of the patterns themselves. Unlike the normal controls, a group of patients with unilateral surgical lesions that included the ANC (15 left, 18 right) did not show conditioned preferences, but performed normally on a measure of working memory. In contrast, 13 patients with unilateral damage confined to frontal cortex exhibited normal conditioned preferences but were impaired on the working memory task. This double dissociation provides clear evidence that, in humans as in other animals, reward-related learning (conditioned reward) critically depends on a circuit involving inferotemporal cortex and the ANC.
Assuntos
Comportamento de Escolha/fisiologia , Condicionamento Psicológico/fisiologia , Lobo Temporal/fisiologia , Adolescente , Adulto , Tonsila do Cerebelo/fisiologia , Mapeamento Encefálico , Neoplasias Encefálicas/cirurgia , Epilepsia/cirurgia , Feminino , Lateralidade Funcional , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The literature on the effects of lesions of the lateral hypothalamic area (LHA) on eating and drinking is reviewed in an effort to understand the function of the neural substrate destroyed. The data suggest that damage to the dopaminergic nigrostriatal neurons that course through the LHA results in a decrease in sensorimotor facilitation; that is, an increase in the threshold for responding to stimuli that elicit orientation, approach and consumption. This increase results in decreased consumption of food and water. Evidence is also reviewed suggesting the possibility that striatal dopaminergic activity may mediate a negative feedback signal related to blood glucose level that influences responsiveness to food, and therefore eating. There is no evidence that the nigrostriatal system mediates a similar signal related to water balance and drinking. A second deficit associated with LHA lesions, caused by damage to the pallidofugal neurons that descend through this area, is a dysfunction of motor control of the head and mouth. This results in an increase in the effort required to consume food and water, also leading to decreased consumption. These two behavioral factors: an increased threshold for responding to the sensory properties of food and water and an increase in the effort required to eat and drink are used to explain the symptoms making up the lateral hypothalamic syndrome without postulating changes in physiological regulatory (set point) mechanisms.
Assuntos
Corpo Estriado/fisiologia , Dopamina/fisiologia , Comportamento de Ingestão de Líquido/fisiologia , Comportamento Alimentar/fisiologia , Substância Negra/fisiologia , Animais , Glicemia/fisiologia , Peso Corporal , Mapeamento Encefálico , Estimulação Elétrica , Retroalimentação , Homeostase , Hidroxidopaminas/farmacologia , Região Hipotalâmica Lateral/fisiologia , Insulina/farmacologia , Masculino , Atividade Motora/fisiologia , Vias Neurais/fisiologia , Oxidopamina , Ratos , Receptores Dopaminérgicos/fisiologia , Resposta de Saciedade/fisiologia , Sensação/fisiologia , Transmissão Sináptica , Paladar/fisiologiaRESUMO
The histories of the terms "reward" and "reinforcement" are reviewed to show the difference in their origins. Reward refers to the fact that certain environmental stimuli have the property of eliciting approach responses. Evidence suggests that the ventral striatum (nucleus accumbens area) is central to the mediation of this behavior. Reinforcement refers to the tendency of certain stimuli to strengthen learned stimulus-response tendencies. The dorsolateral striatum appears to be central to the mediation of this behavior. Neuroanatomical and neurochemical data are adduced suggesting that reward may be mediated by a neural circuit including the neostriatal patch system, together with the hippocampus, limbic system (amygdala, prefrontal cortex) and ventral pallidum. The evidence also suggests that reinforcement, in the form of dopamine release in the striatal matrix, acts to promote the consolidation of sensori-motor associations. Thus, the matrix may mediate stimulus-response memory as part of a circuit including the cerebral cortex, substantia nigra pars reticulata and its projections to thalamic and brainstem motor areas.
Assuntos
Encéfalo/fisiologia , Reforço Psicológico , Recompensa , Animais , Corpo Estriado/fisiologia , Dopamina/fisiologia , Hipocampo/fisiologia , Sistema Límbico/fisiologia , Memória/fisiologia , Núcleo Accumbens/fisiologiaRESUMO
The effectiveness of central parenteral nutrition (CPN) versus peripheral parenteral nutrition (PPN) plus enteral nutrition in reversing protein-energy malnutrition was evaluated in 19 children (nine CPN, 10 PPN) with advanced neuroblastoma or Wilms' tumor. Weekly dietary, anthropometric, and biochemical measurements were compared for 15 patients (eight CPN, seven PPN) who completed more than 25 days of nutrition support. The groups had similar mean energy and protein intakes (CPN: 95 +/- 5% of healthy children, 2.5 +/- 0.3 g/kg; PPN: 102 +/- 5% of healthy children, 2.9 +/- 0.3 g/kg). Increases in weight (p less than 0.001), subscapular skinfold thickness (p less than 0.001), albumin (p less than 0.05), and transferrin (p less than 0.05) for the first 28 days were significant and did not differ between groups. Fever, sepsis, elevated SGOT, and severe anemia occurred with both CPN and PPN. PPN resulted in subcutaneous infiltrations and more psychological trauma. PPN with enteral nutrition seems most appropriate for short term intravenous nutrition support or as a temporary substitute for CPN; CPN is preferred for long-term support.
Assuntos
Nutrição Enteral/normas , Neoplasias Renais/terapia , Neuroblastoma/terapia , Nutrição Parenteral/normas , Desnutrição Proteico-Calórica/terapia , Tumor de Wilms/terapia , Peso Corporal , Criança , Pré-Escolar , Feminino , Humanos , Neoplasias Renais/complicações , Masculino , Neuroblastoma/complicações , Nutrição Parenteral/efeitos adversos , Nutrição Parenteral/métodos , Nutrição Parenteral Total/normas , Desnutrição Proteico-Calórica/complicações , Dobras Cutâneas , Tumor de Wilms/complicaçõesRESUMO
A paraplegic patient who underwent the placement of Greenfield filters to prevent pulmonary emboli had one of the filters migrate proximally to the junction of the inferior vena cava and right atrium, then into the right atrium a few months later. This resulted in an acute myocardial infarction by apparently causing an intimal dissection of the posterior descending artery. Treatment, follow-up and causes of filter migration are discussed.
Assuntos
Migração de Corpo Estranho/complicações , Infarto do Miocárdio/etiologia , Filtros de Veia Cava , Adulto , Angiografia Coronária , Vasos Coronários/lesões , Migração de Corpo Estranho/diagnóstico por imagem , Átrios do Coração , Humanos , Masculino , Veia Cava Inferior/diagnóstico por imagemRESUMO
The effect of posttraining intracerebral injections of the indirect dopamine (DA) agonist d-amphetamine, the direct D2 agonist LY 171555, and the direct D1 agonist SKF-38393 on the acquisition of two 8-arm radial maze tasks were examined. On a win-stay task, a light cue signaled the location of food in 4 randomly selected maze arms on each trial, and animals were required to visit each of the lit arms twice within a trial. Posttraining intracaudate injection of d-amphetamine (10.0 and 15.0 micrograms), LY 171555 (2.0 micrograms), and SKF-38393 (5.0 micrograms) all improved win-stay acquisition in relation to saline-injected controls. In contrast, posttraining intrahippocampal injection of DA agonists had no effect on win-stay acquisition. On a win-shift task, rats were allowed to obtain food from 4 randomly selected maze arms, followed by a delay period in which they were removed from the maze. They were returned to the maze for a retention test in which only those arms that had not been visited before the delay contained food. Posttraining intrahippocampal (but not intracaudate) injection of d-amphetamine (5.0 micrograms), LY 171555 (2.0 micrograms), and SKF-38393 (5.0 micrograms) all improved win-shift retention in relation to saline-injected controls. The results demonstrate a double dissociation of hippocampus and caudate nucleus memory functions and show that posttraining injection of both D1 and D2 agonists modulate the memory processes subserved by both hippocampus and caudate nucleus.
Assuntos
Núcleo Caudado/efeitos dos fármacos , Dopaminérgicos/farmacologia , Hipocampo/efeitos dos fármacos , Rememoração Mental/efeitos dos fármacos , 2,3,4,5-Tetra-Hidro-7,8-Di-Hidroxi-1-Fenil-1H-3-Benzazepina/farmacologia , Animais , Comportamento Apetitivo/efeitos dos fármacos , Mapeamento Encefálico , Dextroanfetamina/farmacologia , Aprendizagem por Discriminação/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ergolinas/farmacologia , Injeções , Masculino , Motivação , Orientação/efeitos dos fármacos , Quimpirol , Ratos , Esquema de Reforço , Retenção Psicológica/efeitos dos fármacosRESUMO
Results of previous experiments have demonstrated that posttraining, noncontingent ingestion of sucrose solutions, or injection of glucose solutions improve retention of various learning tasks. In the present experiment, we tested the hypothesis that this effect is due to a glucose-stimulated release of epinephrine from the adrenal medulla by testing the effect of posttraining glucose injections on retention of a conditioned emotional response (CER) in demedullated rats. In a preliminary experiment, demedullated rats were found to be deficient at acquiring the CER, but a similar deficit in sham-operated animals suggested that this was due to the surgical procedure rather than to the absence of the adrenal medulla. When appropriate shock parameters were used, posttraining glucose improved retention of the CER in a manner parallel to the effect of this treatment in normal rats. It was concluded that the memory improving effect of posttraining glucose does not involve an effect of this substance on the adrenal medulla.
Assuntos
Medula Suprarrenal/fisiologia , Nível de Alerta/fisiologia , Glicemia/metabolismo , Condicionamento Clássico/fisiologia , Medo/fisiologia , Memória/fisiologia , Rememoração Mental/fisiologia , Retenção Psicológica/fisiologia , Animais , Aprendizagem por Associação/fisiologia , Eletrochoque , Epinefrina/sangue , Masculino , Ratos , Ratos EndogâmicosRESUMO
Brain structures thought to be critical for learning and memory were lesioned, and the effects on rats' ability to locate food on a radial maze in situations that provided different types of information was used to suggest general principles of information processing by hypothesized neural systems that include each of the lesioned structures. When animals were confined to food-containing and empty arms on different training trials, the learned discrimination between the arms was amygdala based. More training trials were required for ambiguous (adjacent arms) than for unambiguous (widely separated arms) discriminations. When rats moved around and entered both food and no-food arms on the same trial, the unambiguous discrimination was learned by both dorsal striatum- and hippocampus-based systems; however, the ambiguous discrimination was learned only by the hippocampus system.
Assuntos
Encéfalo/fisiologia , Hipocampo/fisiologia , Aprendizagem em Labirinto/fisiologia , Rememoração Mental/fisiologia , Orientação/fisiologia , Tonsila do Cerebelo/fisiologia , Animais , Comportamento Apetitivo/fisiologia , Aprendizagem por Associação/fisiologia , Mapeamento Encefálico , Corpo Estriado/fisiologia , Aprendizagem por Discriminação/fisiologia , Masculino , Vias Neurais/fisiologia , RatosRESUMO
Rats were trained to run down a runway for either 1 or 10 food pellets. After training, those receiving 10 pellets were shifted to 1 pellet. Such shifts typically elicit a temporary decrease in running speed. Groups of normal rats and rats with bilateral lesions of the fimbria-fornix, lateral-basolateral complex of the amygdala, or dorsal striatum were tested with the shifted and unshifted procedures. Separate experiments, identical except for the intertrial intervals (ITIs; 3 min vs. 30 s), were carried out. The data are consistent with the view that an integrated action of multiple neural systems is required to observe the typical response to reward reduction in unlesioned rats. One system that includes the dorsal striatum promotes a reinforced approach response to the goal box. A neural system that includes fimbria-fornix is required to retain information about reduced reward over the 3-min ITI. A system that includes the amygdala may acquire a conditioned aversive response to the goal box after the shift is detected, leading to reduced speeds over testing.