Estudo sobre o papel da dopamina no desenvolvimento e no comportamento tipo-ansioso em larvas de Zebrafish (Danio rerio) utilizando teste de Labirinto em cruz com rampa adaptado para larvas

Abstract

The use of model animals in behavioral research is increasing. The use of these animals has become more diverse over the years compared to the beginning when only rodents or primates were used for research. Due to the advances in genetic studies, it has been possible to get to know other species compatible at the molecular, genetic and physiological level with the human species. Based on this, the Zebrafish (Danio rerio), a small teleost fish native to the rice fields of India, proved to be a non-mammalian animal with great potential for study within the field of biological sciences. In neurosciences, the use of Zebrafish contributes to studies about behavior, due to its behavioral patterns that resemble human behaviors, which makes this species one of the most used for studies that aim to understand the psychiatric disorders. In this research, we studied the anxiety-like behavior in the larval stage in Zebrafish, in order to understand possible factors in development that contribute to abnormal manifestations of this behavior in later stages of life. In study 1, we adapted an experimental apparatus for larvae that originally assesses anxiety-like behavior in an adult Zebrafish wich is called the plus maze with Ramp. The validation steps of this protocol for larvae were divided into sensitivity tests, where we evaluated the response profile of larvae in different water columns and test session time, and effect of drugs. The results showed sensitivity to the apparatus for the height of the water column in 1.5 cm and 5 minutes of session, and the pharmacological results indicate that the larvae are sensitive to anxiolytic and anxiogenic substances. In study 2, we aimed to understand if behavioral disorders, such as anxiety disorder, are related to the participation of dopaminergic signaling during brain genesis and its relationship to these behavioral changes throughout life. We know that dopamine performs several physiological and behavioral functions, such as motor activity, decision making, among others However, the mechanisms that are involved during the modulation of this neurotransmitter's neurodevelopment are hardly known for this we use zebrafish larvae as a model to investigate the role of dopaminergic receptors in the development of anxiety-like behavior Our results revealed that the increase in dopamine during the 3-5dpf development window showed changes in motor activity and increased anxiety-like behavior in larvae exposed to the Maze in Cruz with Ramp, results also observed in the acute exposures of D1 and D2 agonists.