• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Participa??o do circuito dopamin?rgico nas altera??es do comportamento de medo inato de camundongos infectados pelo Toxoplasma gondii

Meurer, Ywlliane da Silva Rodrigues 26 April 2012 (has links)
Made available in DSpace on 2014-12-17T15:37:13Z (GMT). No. of bitstreams: 1 YwllianeRSM_DISSERT_noPW.pdf: 1856202 bytes, checksum: 7b03b226d479c14a9f1c59d7a70f7f2a (MD5) Previous issue date: 2012-04-26 / The protozoan parasite Toxoplasma gondii transforms the innate aversion of rats for cat urine into a fatal attraction, that increases the likelihood of the parasite completing its life cycle in the cat s intestine. The neural circuits implicated in innate fear, anxiety, and learned fear all overlap considerably, raising the possibility, that T. gondii may disrupt all of these nonspecifically. In this study, we evaluated immunoreactivity for tyrosine hydroxylase (TH) in areas associated with innate fear of infected male swiss mice. The latent Toxoplasma infection converted the aversion of mice to feline odors into attraction. This loss of fear is remarkably specific, as demonstrated by Vyas et al (2007), because infection did not diminish learned fear, anxiety-like behavior, olfaction, or nonaversive learning. However, the neurochemical mechanism related to alterations in innate fear due to T. gondii infection remains poorly studied. 20 mice were inoculated with bradyzoites (25 cysts) from a Toxoplasma gondii (Me-49 strain). The brains were removed after 60 days, sectioned and processed for TH immunohistochemistry. The correlation between the amount of cysts per area and the densitometric analysis of neurotransmitter reactivity was low in the areas implicated in innate fear of infected animals, when comparated with noninfected controls / O protozo?rio Toxoplasma gondii transforma a avers?o inata de ratos ? urina de gato em atra??o. Essa mudan?a pode aumentar a probabilidade de transmiss?o do parasito para o seu hospedeiro definitivo, os felinos, onde pode se reproduzir sexualmente. Os circuitos neurais envolvidos no medo inato, ansiedade ou medo aprendido se sobrep?em consideravelmente, aumentando a possibilidade de que o T. gondii possa interferir com todos de maneira n?o-espec?fica. Neste estudo, foi avaliada a imunorreatividade para tirosina hidroxilase (TH) em ?reas dopamin?rgicas relacionadas com o medo inato em camundongos sui?os machos infectados. A infec??o latente pelo parasita inverteu a avers?o aos odores de felinos. Esta modifica??o pode estar relacionada com a presen?a dos cistos na am?gdala, pois a infec??o n?o diminui medo aprendido, a ansiedade, o olfato, ou a aprendizagem n?o-aversiva. No entanto, o mecanismo neuroqu?mico relacionado a estas altera??es no medo inato durante a infec??o permanece pouco estudado. Os animais foram infectados com bradizo?tos (25 cistos) da cepa ME-49 de T. gondii. Os c?rebros foram removidos ap?s 60 dias, seccionados e processados para revelar a reatividade da enzima TH. Os cistos foram contados nas ?reas associadas ao circuito dopamin?rgico, bem como em regi?es relacionadas ao medo inato. A contagem por ?rea e a an?lise densitom?trica mostrou baixa rela??o entre a presen?a de cistos e a reatividade para TH regi?es de interesse nos animais infectados, quando comparados aos controles n?o-infectados

Page generated in 0.1102 seconds