O papel do receptor serotoninérgico 5-ht1a no comportamento tipo-ansiedade em ensaio biocomportamental

Abstract

Anxiety is a normal emotion representing a reaction to potential danger, whereas fear can be defined as a reaction to real, explicit danger. When pathological, anxiety can be detrimental to an individual's quality of life as it becomes persistent, uncontrollable and inappropriate. Epidemiologic data show how anxiety can be detrimental at both economic and social levels, as well as being considered a public health problem. Related to some physiological and behavioral functions such as anxiety states is the 5-HT1A receptor, which is part of the serotonergic (5-HT) system. The use of model organisms for the assessment of biobehavioral phenomena is important to substantiate hypotheses about the biological basis of these phenomena. With this in mind, the zebrafish (Danio rerio), also known as paulistinha or zebrafish, is an ideal model organism to study the role of this receptor in behavior, due to both the homologies described between the 5-HT1A receptor of mammals and teleost fish and the functional similarities of the serotoninergic system. Based on the literature, we hypothesize that activation of the 5-HT1A receptor will produce increased anxiety-like behavior in this animal. Treatment of zebrafish cohorts with 8-OH-DPAT, a full agonist of the 5-HT1A receptor, decreased anxiety-like behavior in the novelty-elicited vertical distribution test, but not in the light-dark preference test, both considered endpoints of anxiety-like behavior for this species. The same treatment decreased social approach in both the social investigation test and social novelty test. These effects suggest a participation of the 5-HT1A heteroreceptors in zebrafish anxiety and social preference, decreasing both. Thus, the study of this receptor is important for a better understanding of anxiety-like behavior in zebrafish and its relationship with similar phenomena in vertebrates.