masterThesis
Participação do circuito dopaminérgico nas alterações do comportamento de medo inato de camundongos infectados pelo Toxoplasma gondii
Fecha
2012-04-26Registro en:
MEURER, Ywlliane da Silva Rodrigues. Participação do circuito dopaminérgico nas alterações do comportamento de medo inato de camundongos infectados pelo Toxoplasma gondii. 2012. 61 f. Dissertação (Mestrado em Estudos de Comportamento; Psicologia Fisiológica) - Universidade Federal do Rio Grande do Norte, Natal, 2012.
Autor
Meurer, Ywlliane da Silva Rodrigues
Resumen
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