Conspecific alarm substance differently alters group behavior of zebrafish populations: Putative involvement of cholinergic and purinergic signaling in anxiety- and fear-like responses

• Published in: Behavioural brain research 2017-03, Vol.320, p.255-263
• Main Authors: Canzian, Julia, Fontana, Barbara D., Quadros, Vanessa A., Rosemberg, Denis B.
• Format: Article
• Language: English
• Subjects: 5'-Nucleotidase - metabolism; Acetylcholinesterase; Acetylcholinesterase - metabolism; Alarm substance; Analysis of Variance; Animals; Animals, Genetically Modified; Anxiety - metabolism; Area Under Curve; Behavior, Animal - physiology; Defensive behavior; Escape Reaction - physiology; Fear; Female; Male; Nucleotide hydrolysis; Shoaling; Zebrafish; Zebrafish Proteins - genetics; Zebrafish Proteins - metabolism
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2016.12.018

[Display omitted] •Alarm substance induces fear in zebrafish shoals of two populations.•Leo shoals show pronounced basal defensive responses in comparison to WT fish.•Only WT shows enhanced shoaling and diving response triggered by alarm substance.•The cholinergic and purinergic systems may play a role in defensive behaviors. The zebrafish (Danio rerio) is an emergent model organism for assessing fear and anxiety-like phenotypes. The short fin wild type (WT), and leopard (leo) are two zebrafish populations that present several behavioral differences, in which leo displays pronounced defensive responses. Mounting evidence suggests a modulatory role for cholinergic and purinergic signaling in fear and anxiety, but the involvement of these neurotransmitter systems in the behavioral profile of zebrafish is obscure. Here we tested whether the acute exposure to conspecific alarm substance (AS), an experimental protocol that induces fear, alters shoaling behavior, diving response, acetylcholinesterase (AChE) activity, and nucleotide hydrolysis in brain tissue of WT and leo. When four fish were concomitantly exposed to AS extracted from a donor fish of similar phenotype, both populations presented a significant increase of erratic movements without changes in freezing bouts. An increased shoal cohesion and a decreased vertical distribution were observed only in WT exposed to AS. The respective population also revealed a significant increase in AChE and ecto-5′-nucleotidase activities after the exposure period. The comparison of basal endpoints between populations showed that leo displays a higher social cohesion, few vertical transitions and enhanced AChE and ecto-5′-nucleotidase activities. In conclusion, we suggest that the effects of AS on defensive behaviors depend on the population, indicating the existence of distinct neurochemical mechanisms involved. Furthermore, this report shows the first evidence of a potential role of cholinergic and purinergic systems in fear- and anxiety-like responses of zebrafish populations.