4 resultados para Collective memory

em Repositório da Produção Científica e Intelectual da Unicamp


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Previous research has shown that crotamine, a toxin isolated from the venom of Crotalus durissus terrificus, induces the release of acetylcholine and dopamine in the central nervous system of rats. Particularly, these neurotransmitters are important modulators of memory processes. Therefore, in this study we investigated the effects of crotamine infusion on persistence of memory in rats. We verified that the intrahippocampal infusion of crotamine (1 μg/μl; 1 μl/side) improved the persistence of object recognition and aversive memory. By other side, the intrahippocampal infusion of the toxin did not alter locomotor and exploratory activities, anxiety or pain threshold. These results demonstrate a future prospect of using crotamine as potential pharmacological tool to treat diseases involving memory impairment, although it is still necessary more researches to better elucidate the crotamine effects on hippocampus and memory.

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The article discusses the possibility of applying Kuhn's concept of paradigm to collective health. The concept and its use in epidemiology, planning and the social sciences are reviewed briefly. The study stresses the multi-paradigmatic character of collective health, resulting from the convergence of multiple epistemologies and the involvement of diverse fields such as the biological sciences, philosophy, the social sciences and humanities.

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The mechanism underlying castration-induced prostate regression, which is a classical physiological concept translated into the therapeutic treatment of advanced prostate cancer, involves epithelial cell apoptosis. In searching for events and mechanisms contributing to prostate regression in response to androgen modulation, we have frequently observed the collective deletion of epithelial cells. This work was undertaken to characterize this phenomenon hereafter named desquamation and to verify its presence after 17β-estradiol (E2) administration. Electron microscopy revealed that the desquamating cells had preserved cell-cell junctions and collapsed nuclear contents. The TUNEL reaction was negative for these cells, which were also negative for cleaved caspases-8, -9, -3 and nuclear apoptosis-inducing factor. Detailed analyses revealed that the condensed chromatin was first affected detaching from the nuclear lamina, which was observable after lamin A immunohistochemistry, suggesting the lack of lamin A degradation. A search in animals treated with supraphysiological E2 employed as an alternative anti-androgen treatment revealed no desquamation. The combined treatment (Cas + E2 group) caused changes particular to each treatment, including desquamation. In conclusion, desquamation appeared as a novel phenomenon contributing to collective prostate epithelial cell deletion, distinct from the classical castration-induced apoptosis and particular to the androgen deprivation resulting from surgical castration, and should be considered as part of the mechanisms promoting organ regression.

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Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) functions both in regulation of insulin secretion and neurotransmitter release through common downstream mediators. Therefore, we hypothesized that pancreatic ß-cells acquire and store the information contained in calcium pulses as a form of metabolic memory, just as neurons store cognitive information. To test this hypothesis, we developed a novel paradigm of pulsed exposure of ß-cells to intervals of high glucose, followed by a 24-h consolidation period to eliminate any acute metabolic effects. Strikingly, ß-cells exposed to this high-glucose pulse paradigm exhibited significantly stronger insulin secretion. This metabolic memory was entirely dependent on CaMKII. Metabolic memory was reflected on the protein level by increased expression of proteins involved in glucose sensing and Ca(2+)-dependent vesicle secretion, and by elevated levels of the key ß-cell transcription factor MAFA. In summary, like neurons, human and mouse ß-cells are able to acquire and retrieve information.