Environmentally relevant stressors alter memory formation in the pond snail Lymnaea

Stress alters adaptive behaviours such as learning and memory. Stressors can either enhance or diminish learning, memory formation and/or memory recall. We focus attention here on how environmentally relevant stressors alter learning, memory and forgetting in the pond snail, Lymnaea stagnalis. Operant conditioning of aerial respiration causes associative learning that may lead to long-term memory (LTM) formation. However, individual ecologically relevant stressors, combinations of stressors, and bio-active substances can alter whether or not learning occurs or memory forms. While the behavioural memory phenotype may be similar as a result of exposure to different stressors, how each stressor alters memory formation may occur differently. In addition, when a combination of stressors are presented it is difficult to predict ahead of time what the outcome will be regarding memory formation. Thus, how combinations of stressors act is an emergent property of how the snail perceives the stressors.</jats:p

Acompanhamento de pacientes submetidos à cirurgia bariátrica : aspectos laboratoriais nos períodos pré e pós-operatório

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Farmácia, Florianópolis, 2017A obesidade é uma doença crônica e endócrino-metabólica caracterizada pelo acúmulo excessivo de triacilgliceróis no tecido adiposo, capaz de ser revertida ou amenizada através de intervenção cirúrgica. Epidemiologicamente têm sido descritas associações entre o excesso de peso, resistência à insulina e processo inflamatório crônico. Além disso, nas últimas décadas o sistema complemento foi associado a doenças metabólicas e cardiovasculares e intimamente relacionado com a obesidade e resistência à insulina. Sendo assim, a melhora do estado metabólico e a remissão da inflamação em pacientes obesos submetidos à cirurgia bariátrica foram avaliadas, bem como a associação dos fatores 3 e 4 (C3 e C4) do sistema complemento com a sensibilidade à insulina e a perda de peso após a cirurgia bariátrica. Para isso, a presença de comorbidades e as concentrações séricas de leptina, adiponectina, resistina e grelina foram avaliados em pacientes obesos mórbidos antes, 1, 3 e 6 meses após a cirurgia bariátrica. Também foram medidas as concentrações de IL-1ß, IL-6, TNF-a, proteína amiloide sérica A (SAA), proteína quimiotática de monócitos 1 (MCP-1), C3, C4, glicose, insulina, colesterol total, triacilglicerol, LDL- colesterol, HDL-colesterol e foi realizado o cálculo do modelo de avaliação da homeostase da resistência à insulina (HOMA-IR) durante o seguimento da cirurgia, bem como em comparação com um grupo de indivíduos não-obesos. Como resultado, observou-se uma redução significativa de peso acompanhada de melhora do perfil lipídico, da sensibilidade à insulina e das comorbidades. Ainda, houve diminuição de leptina e aumento de adiponectina no período pós-cirúrgico. IL-1ß, IL-6, TNF-a, MCP-1 e SAA não mostraram diferença no acompanhamento da cirurgia, porém SAA correlacionou-se com o IMC e apresentou-se muito mais alto no grupo de pacientes obesos. Além disso, C3 e C4 foram significativamente maiores em indivíduos obesos quando comparados aos indivíduos não-obesos e C3 e C4 foram positivamente correlacionados com HOMA-IR e as concentrações de C3 foram significativamente diminuídas após a cirurgia. Com base nesses resultados, a cirurgia bariátrica mostrou melhorar o estado metabólico melhorando as comorbidades associadas à obesidade e os biomarcadores de adiposidade leptina e adiponectina, mas não os demais hormônios e citocinas inflamatórias e C3 e C4 foram fortemente associados à sensibilidade à insulina.Abstract: Obesity is a chronic and endocrine-metabolic disease characterized by triacylglycerol accumulation in the adipose tissue, which can be reversed or improved through surgical intervention. Epidemiologically, associations between overweight, insulin resistance and chronic inflammatory process have been described. Furthermore, in the last decades the complement system was associated with metabolic and cardiovascular diseases and related to obesity and insulin resistance. Thus, metabolic status improvement and inflammation remission in obese patients undergoing bariatric surgery were evaluated, as well as the association of complement system factors 3 and 4 (C3 and C4) with insulin sensitivity and weight loss after bariatric surgery. For this, comorbidities and leptin, adiponectin, resistin and ghrelin serum concentrations were evaluated in morbidly obese patients before, 1, 3 and 6 months after bariatric surgery. IL-1ß, IL-6, TNF-a, serum amyloid A protein (SAA), monocyte chemotactic protein 1 (MCP-1), C3, C4, glucose, insulin, total cholesterol, triacylglycerol, LDL-cholesterol, HDL-cholesterol concentrations and the calculation of the homeostasis model of insulin resistance (HOMA-IR) were performed during the surgery follow-up, as well in a group of non-obese individuals. As a result, significant weight loss followed by improvement in lipid profile, insulin sensitivity and comorbidities were observed. Still, there was a decrease in leptin and an increase in adiponectin in the postoperative period. IL-1ß, IL-6, TNF-a, MCP-1 and SAA showed no difference after surgery, but SAA correlated with BMI and was much higher in obese patients. In addition, both C3 and C4 were significantly higher in obese individuals when compared to lean individuals and positively correlated with HOMA-IR. C3 concentrations were significantly decreased after surgery. Based on these results, bariatric surgery has been shown to improve metabolic status by improving obesity-associated comorbidities and adiposity biomarkers leptin and adiponectin but not the other hormones and inflammatory cytokines and C3 and C4 were strongly associated with insulin sensitivity

RPeD1 burst activity in naïve versus trained <i>Lymnaea</i>.

<p>Mean (±SEM) burst activity in RPeD1 in naïve <i>Lymnaea</i>, 3 h following training (i.e. representing intermediate-term memory test) and 24 h following training (i.e. representing long-term memory test) following exposure to: A) control conditions (white bars: naïve: N = 11; ITM: N = 9; LTM: N = 9); B) low calcium availability (pale grey bars: naïve: N = 10; ITM: N = 7; LTM: N = 6); C) crowding (dark grey bars: naïve: N = 9; ITM: N = 10; LTM: N = 10) or D) a combination of low calcium availability and crowded conditions (black bars: naïve: N = 9; ITM: N = 13; LTM: N = 10). *  =  significant difference between naïve and trained bursting behaviour (P<0.05: SNK test).</p

Behavioural assessment of intermediate-term and long-term memory.

<p>Mean (± SEM) number of pneumostome opening attempts during training (TR1 and TR2) and the test for intermediate-term memory 3 h following training (A to D: test @ 3 h) or long-term memory 24 h following training (E to H: test @ 24 h). <i>Lymnaea</i> were exposed to:control conditions (white bars: A: N = 18; E: N = 13); low calcium availability (pale grey bars: B: N = 18; F: N = 12); crowding (dark grey bars: C: N = 18; G: N = 12) or a combination of low calcium availability and crowded conditions (black bars: D: N = 18; H: N = 12). **  =  significant difference between the first training session (TR1) and second training session (TR2) or the memory test (P<0.01, paired t-test).</p