An approach to evaluate the ability of rats to discriminate different levels of illumination in the plus maze test: effects of scopolamine.
Behav Brain Res
; 180(1): 86-94, 2007 Jun 04.
Article
em En
| MEDLINE
| ID: mdl-17408761
ABSTRACT
Previous research has shown that the visual system is important for rats to establish the arm preference in the elevated plus maze (EPM), an animal model of anxiety. This study aims at evaluating whether a gradient of illumination between the enclosed arms of the maze (E/E(DeltaLux)) could be a reliable approach to detect drugs-induced harmful effect on visual discrimination of rats. Four EPM configurations with different E/E(DeltaLux) (8, 41 and 85lx) were used to demonstrate that as E/E(DeltaLux) increases, rats avoid to explore the light enclosed arm, which characterizes the animal ability to discriminate the most illuminated area within the protected environment of the maze. The establishment of either 41 or 85 E/E(DeltaLux) failed to alter the traditional spatial-temporal variables in the EPM. In addition, systemic treatment with midazolam (MDZ; 1.0mgkg(-1), a classical anxiolytic) induced anxiolysis in rats tested in 41 and 85 E/E(DeltaLux) EPM, with no change in the visual discrimination, when evaluated by the level of light enclosed arm exploration. Systemic treatment with scopolamine (SCP; 1.0, 2.0 and 8.0mgkg(-1)), a drug endowed with harmful properties upon the visual system, did not change either the open arm avoidance or the visual discrimination at the low doses, but induced increased light enclosed arm (visual discrimination deficit) and open arm exploration (anxiolytic like effect) at a higher dose. We propose that the incorporation of an E/E(DeltaLux) in the EPM may reinforce the predict validity of the test since it enables to evaluate whether a visual discrimination deficit can be confounded with an anxiolytic-like effect, thus establishing a false positive detection.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Escopolamina
/
Aprendizagem da Esquiva
/
Ansiolíticos
/
Percepção Visual
/
Iluminação
/
Aprendizagem por Discriminação
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Behav Brain Res
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Brasil