Alcohol exposure and environmental enrichment effects on contextual fear conditioning in zebrafish

• Published in: Behavioural processes 2022-04, Vol.197, p.104608-104608, Article 104608
• Main Authors: Menezes, Fabiano P., Amorim, Ricardo R., Silva, Priscila F., Luchiari, Ana C.
• Format: Article
• Language: English
• Subjects: Animals; Behavior, Animal; Conditioning, Psychological; Danio rerio; Electroshock; Ethanol; Ethanol - pharmacology; Fear; Fear/anxiety; Holding conditions; Learning; Zebrafish
• ISSN: 0376-6357; 1872-8308
• DOI: 10.1016/j.beproc.2022.104608

Environmental enrichment effectively reduces anxiety-like indicators in animals, a potential co-treatment for diseases that generate variations in basal anxiety, such as alcoholism. Here we present an experimental design that allows investigating the effect of enrichment on anxiety-related behaviors using contextual aversive conditioning in zebrafish (Danio rerio). It was first observed whether animals conditioned with an aversive stimulus (electroshock paired with checked background tank) exhibited behavioral variations when previously held in barren (BE) or enriched (EE) environment. Enrichment reduced anxiety-like behaviors. Then, fish was exposed to four alcohol concentrations (0.00%, 0.10%, 0.50%, and 1.00%) after being held in BE or EE, and contextual fear conditioning was tested again. Fish showed dose-dependent and enrichment-related variation in anxiety-like behavior. Together, these results indicate that the experimental design in question is efficient in measuring behavior related to BE and EE, and that enrichment seems to impair the acquisition of dose-dependent effects of alcohol. Our results show that EE can alleviate deleterious effects caused by traumatic events, but it should also consider some effects of enrichment and alcohol exposure interaction. •Memory of an aversive event (shock) triggered by a context leads to anxiety.•Enriched holding condition acts as anxiolytic when fish face the fear context.•Low alcohol concentration alleviated anxiety only in baren environment held animals.•Higher alcohol concentration effects were reduced in enriched held animals.•Holding environment interacts with alcohol exposure to promote behavioral alterations.