Tese
Avaliação dos efeitos morfofisiológicos e comportamentais em camundongos jovens submetidos ao estresse por separação maternal em conjunto com administração de L-Dopa
Fecha
2021-08-31Autor
Ana Luiza de Araujo Lima Reis
Institución
Resumen
Early life stress can lead to behavioral changes commonly associated with many of the
neuropsychiatric disorders, including anxiety and depression. Several of these disorders appear
during adolescence, when brain remodeling takes place. This is one of the reasons why the
practice of child/adolescent psychiatry and preventive approaches is still a challenge. Therefore,
we investigated the effects of maternal separation (MS) stress on the behavior of prepubertal
mice. One of the challenges in psychiatry studies is the sexual bias in the prevalence of some
mental disorders. To address this issue, we used C57 / BL6 male and female mice. At 4 weeks
of age, we analyzed the behavior of the animals through locomotor activity box tests, open field
test, light/dark box, elevated plus maze, novelty suppressed feeding test and forced swimming
test. We have seen that postnatal stress led to an increase in exploratory and locomotor behavior
in females and an increase in anxious-like and depressive-like behavior in males. In addition to
the fact that several dopaminergic genes are associated with neuropsychiatric disorders and the
dopaminergic system is the target of many pharmacological treatments, it is known that chronic
stress generates imbalances in dopaminergic signaling. We then investigated whether increased
dopaminergic tone through L-Dopa administration, in conjunction with MS stress, amplifies or
reduces behavioral consequences in prepubertal mice. We divided the mice into four
experimental groups: treated with saline solution (SAL); Group treated with L-Dopa /
Benserazide (DOPA); MS treated daily with Saline (MS+SAL); and group treated with L-Dopa
/ Benserazide during MS (MS+DOPA). We saw that L-Dopa administration provided less
aversion to more aversive environments in females and an increase in fearful behavior in males.
We also saw that increased dopaminergic tone during postnatal stress was able to alter the
behavioral effects of stress and our results suggest a sexual dimorphism in response to L-Dopa
treatment during the maternal separation protocol.