Exposição perinatal ao chumbo: efeitos da associação de diferentes condições estressogênicas sobre a reatividade vascular e o comportamento de ratos recém-desmamados e adultos
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Data
2008-08-04
Autores
Thomassian, Larissa Tercilia Grizzo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O sistema de estresse coordena a resposta adaptativa ao estímulo estressor e desempenha papel importante na manutenção da homeostase frente a condições estressogênicas. A ativação desse sistema leva a alterações comportamentais e periféricas que aumentam a habilidade do organismo de se adaptar e, portanto, aumentam as suas chances de sobrevivência. Respostas inadequadas ou prolongadas aos estressores podem prejudicar o crescimento e o desenvolvimento e resultar numa grande variedade de desordens de natureza endócrina, metabólica, cardiovascular ou comportamental. A exposição ao estresse determina respostas adaptativas tanto sobre a reatividade vascular quanto sobre o comportamento de ratos. Ainda, o comportamento de ratos não estressados ou submetidos ao estresse pode sofrer influência de experiências estressogênicas perinatais. Finalmente, a resposta ao estresse pode ser alterada por estados patológicos particulares, como hipertensão, intoxicação por metais pesados como o chumbo (Pb), entre outros fatores. Os objetivos foram investigar: 1) as alterações na resposta vascular e no comportamento de ratos jovens e adultos submetidos ou não ao estresse agudo e/ou crônico em diferentes fases do desenvolvimento; 2) se a habilidade em gerenciar o estresse difere entre proles submetidas ou não à intoxicação perinatal por Pb e 3) a participação do endotélio na resposta vascular adaptativa ao estresse em ratos intoxicados ou não. Foram realizadas curvas concentração-efeito à noradrenalina (NA) em aortas torácicas com (+E) e sem endotélio (-E), de ratos jovens (23 dias) e adultos (70 dias) intoxicados perinatalmente por Pb ou não e submetidos ou não ao estresse agudo de imobilização (IM, 2h imediatamente antes dos protocolos experimentais) e/ou crônico de separação materna (SM, 4h/dia por 3 semanas consecutivas). O comportamento dos animais...
The stress response is subserved by the stress system which plays a key role in the maintenance of homeostasis. The human body and mind react to stress by activating a complex repertoire of physiologic and behavioral central nervous system and peripheral adaptive responses, which, if inadequate or excessive and/or prolonged, may affect personality developmental and behavior, and may have adverse consequences on physiologic functions, such as growth, metabolism, circulation and reproduction. The exposure to stressors may induce alterations in the cardiovascular system and behavior, which are related to adaptative processes that can be modified by previous exposure to environmental hazard like plumb or hypertension. The objective was to investigate: the alterations of both vascular reactivity and behavior of 23 days-old and 70 days-old rats exposed to lead during pregnancy and postnatal period and submitted or not to acute and chronic stress; and if the endothelium of intoxicated rats modulate the vascular adaptative response to stress. Concentration effect curves to noradrenaline were obtained in aorta, with and without endothelium of weaned and adult rats of rats exposed or not to Pb and submitted or not to acute (immobilization) or chronic stress (maternal separation, for 4h during 3 weeks), or both. The behavior was measured by open-field and elevated plus-maze. Pb exposed rats showed a decreased vascular reactivity to noradrenaline when submitted to acute stress or acute stress plus chronic one compared with weaned rats exposed to Pb but not to stress conditions. No reactivity alteration in the sensitivity to noradrenaline was observed in aorta with endothelium from weaned rats exposed to the different protocols. The exposure of non intoxicated rats to acute stress and chronic plus acute The exposure of non intoxicated rats to acute stress and chronic plus acute stress determined... (Complete abstract click electronic access below)
The stress response is subserved by the stress system which plays a key role in the maintenance of homeostasis. The human body and mind react to stress by activating a complex repertoire of physiologic and behavioral central nervous system and peripheral adaptive responses, which, if inadequate or excessive and/or prolonged, may affect personality developmental and behavior, and may have adverse consequences on physiologic functions, such as growth, metabolism, circulation and reproduction. The exposure to stressors may induce alterations in the cardiovascular system and behavior, which are related to adaptative processes that can be modified by previous exposure to environmental hazard like plumb or hypertension. The objective was to investigate: the alterations of both vascular reactivity and behavior of 23 days-old and 70 days-old rats exposed to lead during pregnancy and postnatal period and submitted or not to acute and chronic stress; and if the endothelium of intoxicated rats modulate the vascular adaptative response to stress. Concentration effect curves to noradrenaline were obtained in aorta, with and without endothelium of weaned and adult rats of rats exposed or not to Pb and submitted or not to acute (immobilization) or chronic stress (maternal separation, for 4h during 3 weeks), or both. The behavior was measured by open-field and elevated plus-maze. Pb exposed rats showed a decreased vascular reactivity to noradrenaline when submitted to acute stress or acute stress plus chronic one compared with weaned rats exposed to Pb but not to stress conditions. No reactivity alteration in the sensitivity to noradrenaline was observed in aorta with endothelium from weaned rats exposed to the different protocols. The exposure of non intoxicated rats to acute stress and chronic plus acute The exposure of non intoxicated rats to acute stress and chronic plus acute stress determined... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Intoxicação - Estudos experimentais, Chumbo - Envenenamento, Farmacologia
Como citar
THOMASSIAN, Larissa Tercilia Grizzo. Exposição perinatal ao chumbo: efeitos da associação de diferentes condições estressogênicas sobre a reatividade vascular e o comportamento de ratos recém-desmamados e adultos. 2008. 82 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2008.