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Previous issue date: 2007 / Associação Fundo de Incentivo à Psicofarmacologia (AFIP) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Centro de Pesquisa, Inovação e Difusão (CEPID) / A sindrome da apneia e hipoapneia obstrutiva do sono (SAOS) caracteriza-se por epis6dios recorrentes de obstrucao das vias aereas superiores e esta associada as comorbidades cardiovasculares e cognitivas. Nos pacientes apneicos nao e possivel determinar se essas consequencias estao relacionadas aos efeitos da hipoxia per se ou se ocorrem devido a fragmentacao do sono. Assim, propoe-se neste estudo a avaliacao das alteracoes comportamentais, cognitivas e cardiovasculares em um modelo animal que associa hipoxia a privacao de sono. Ratos Wistar machos adultos foram expostos a hipoxia intermitente (HI-ciclos de 2 min de 21 por cento a 10 por cento de O2) das 7 as 19h e/ou privacao de sono paradoxal (PSP) pelo metodo da plataforma unica durante tres ou quatro dias. Para observar os efeitos cronicos da exposicao a HI e/ou restricao de sono (RS), os animais foram expostos a hipoxia das 10 as 16h e/ou submetidos a RS das 16 as 10h do dia seguinte durante 21 dias. Os resultados obtidos nesse estudo indicam que a PSP induziu alteracoes comportamentais associadas a modificacao da neurotransmissao adrenergica. A exposicao cronica a HI reduziu a concentracao de noradrenalina no estriado, modulando seletivamente os sistemas de neurotransmissao sem modificar o comportamento e a funcao cognitiva dos ratos. No entanto, o aumento da atividade motora nos ratos do grupo RS nao foi associado a alteracoes nas concentracoes de catecolaminas e na expressao da enzima tirosina hidroxilase no sistema nervoso central. A exposicao a RS nao modificou a aquisicao e a retencao da memoria dos animais na tarefa de esquiva inibitoria; entretanto, durante a habituacao foi observado prejuizo cognitivo. A PSP e a RS modificaram os fatores bioquimicos associados ao risco cardiovascular. Embora as alteracoes induzidas pela HI nos parametros bioquimicos sanguineos sejam tempo-dependentes, a exposicao a HI associada a PSP reverteu as modificacoes induzidas pela PSP. Os resultados sugerem que a hipoxia e a privacao de sono modificam os sistemas nervoso central e cardiovascular por vias distintas / Obstructive sleep apnea (OSA) is characterized by repetitive obstruction of the
upper airways resulting in pauses in breathing and subsequent oxygen desaturation
and is associated with cardiovascular and cognitive comorbidities. However, it is not
possible to determine whether such effects in apneic patients are related to hypoxia
per se or whether they occur due to the frequency of arousals induced by breathing
alterations during sleep. Thus, this study was designed to determine the isolated
and combined effects of hypoxia and sleep loss in behavior, cognitive and blood
parameters related to cardiovascular risk in rats. Wistar male rats were exposed to
intermittent hypoxia (IH) during the light period (2 min room air - 2 min 10% O2 for
12h/day) and/or paradoxical sleep deprivation (PSD - 24h/day) using the single
platform method. Consequences of chronic IH and/or sleep restriction (SR)
exposure were examined after 21 consecutive days of the hypoxia protocol from
1000-1600h followed by an SR period of 18h (1600 -1000h). Results showed that
PSD induced behavioral alterations associated to modification of adrenergic
neurotransmission. Chronic exposure to IH reduced the concentration of
norepinephine in the striatum, without modifying behavior and cognitive function in
rats. Indeed, the increase of motor activity observed in rats of the SR group was not
associated with the alterations in the concentration of catecholamine and tyrosine
hydroxylase protein expression in the central nervous system. Exposure to SR did
not affect acquisition/retention on the inhibitory avoidance task. PSD (4 days) and
SR (21 days) modified the biochemical factors associated with cardiovascular risk.
Although the alterations that were induced by IH in biochemical parameters of blood
are time dependant, exposure to IH associated with PSD reversed the alterations
induced by PSD. Our results suggest that hypoxia and sleep loss modify
cardiovascular and central nervous systems in distinct ways. / FAPESP: 04/04008-7 / CEPID: 98/14303-3 / BV UNIFESP: Teses e dissertações
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.unifesp.br:11600/23625 |
| Date | January 2007 |
| Creators | Perry, Juliana Cini [UNIFESP] |
| Contributors | Universidade Federal de São Paulo (UNIFESP), Tufik, Sergio [UNIFESP] |
| Publisher | Universidade Federal de São Paulo (UNIFESP) |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | 200 f. |
| Source | reponame:Repositório Institucional da UNIFESP, instname:Universidade Federal de São Paulo, instacron:UNIFESP |
| Rights | info:eu-repo/semantics/openAccess |
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