Efeitos do tipo ansiolítico e antiestresse da taurina em peixe-zebra (Danio rerio)

Abstract

Mental disorders are a major challenge to global health, considered 21st century pandemics. About a third of the world's disability is caused by mental health problems. Faced with this situation, World Health Organization developed an action plan, which searches new strategies for promotion and prevention in mental health, and strengthening research in the area. Therefore, studies aimed at discovering new therapies in the area of mental health become attractive. Taurine has been studied as an adjuvant therapy in disorders of the central nervous system (CNS), due to the potential to prevent the glutamate excitotoxicity, calcium regulation, inflammatory processes and oxidative stress. Herein, we looking for to better understand the actions of taurine as a treatment for mental disorders in humans through zebrafish (Danio rerio) as a model organism. In a systematic review, we describe its main contributions and limitations as a model organism, assessing the central effects of taurine in neuropsychiatric diseases. Finally, we conclude that zebrafish is a model organism with great potential for assessing the neuroprotective effects of taurine in these diseases. Then, we investigated the effects of three concentrations of taurine (42, 150, 400 mg / L) on behavioral models of stress and anxiety in zebrafish. We found that taurine modulates the behavioral and neuroendocrine responses in this species in different contexts. In the first experiment, the fish were tested in the novel tank and light-dark test after treatment with taurine. We did not observe any behavioral difference in the novel tank, only in the light-dark test. All concentrations of taurine prevented the anxiety-like behavior (scotaxis) in fish, allowing them to spend more time in the light area, indicating anxiolytic activity. In the second experiment, the fish were challenged with an acute mechanical stressor (net chasing) or chemical stressor (coespecific alarm substance; CAS) in the same previous behavioral tests. All concentrations of taurine prevented stress-related behaviors triggered by CAS. The lower concentration of taurine also prevented the protein carbonylation caused by chasing with a net, suggesting e possible antioxidant activity. However, the higher concentration stimulated excessively both oxidative parameters and antioxidants triggered by the two stressors. The higher taurine concentration also inhibited the release of cortisol in response to CAS, indicating a possible anti-stress action. Although the phenotypes presented here represent a complex response to multifaceted interactions of various neurotransmitter systems, we believe that taurine can exert a therapeutic action on stress-related mental disorders.