O papel do receptor 5ht2c no comportamento tipo ansiedade em zebrafish (Danio Rerio Hamilton 1822)

Abstract

Anxiety disorders are often disabling and are showing increasing numbers globally. Experimental psychopathology is an area of study of the psychic phenomena that generate such a disorder, often using experiments with animal models in search of possible causes and treatments. The involvement of the serotonergic system in this disorder is identified. This system is made up of several receptors, such as 5-HT2C. In general, it is known that 5-HT2C agonists increase anxiety behaviors, but their role in mood disorders remains controversial. The zebrafish (Danio rerio) can serve as an interesting animal model to delve deeper into the topic, as it combines the relevance of being a vertebrate with the scale of an invertebrate that requires a small space for its maintenance, low cost and practicality for large-scale screening. The present study aims to describe the role of the 5-HT2C receptor in behavioral tests related to anxiety. For this, three groups of fish were used: a group treated with the drug MK-212, a 5HT2C receptor agonist; another group treated with the drug RS-102221, a 5-HT2C receptor antagonist; and a third group, the control group, using a vehicle solution. The three groups were exposed to two behavioral tests: novelty-elicited vertical distribution (DVEN) and light-dark preference (PCE). MK-212 produced no effects on DVEN, while RS-102221 decreased geotaxis in this test; these effects are consistent with a tonic arousal of anxiety in the DVEN. In PCE, the drugs MK-212 and RS-102221 did not produce significant effects. Thus, tonic effects of the activation of this receptor are observed depending on the type of behavioral test used.