Abstract

Depression and other stress-related affective disorders are serious CNS pathologies with recurrent nature and poor treatment outcomes in clinical practice. Relatively well studied in rodents, depression-like phenotype in fish remains obscure. Here we have attempted to model zebrafish despair-like behavior using low voltage electric stimuli to cause avoidance. Briefly, fish were placed in a standard Novel Tank Test (20 x 20 x 5 cm) filled with water 5 cm deep, for 5 min after 20-min exposition to 5 mg/L fluoxetine or drug-free vehicle in 0.5-L beaker (n=15). Back- and sidewalls of tank were covered with white film to direct escape attempts to the clear frontal side of the tank. Wire ends were attached to the opposite sidewalls and current was set to 0.1 V/cm of water. Using manual scoring, we have been accessed frequency (n) and time spent near transparent wall (s), and average time spent near wall (s), erratic movements (n) and number and time spent freezing (n, s). For statistical analysis, we used Mann-Whitney U test to compare cumulative endpoints, and two-way ANOVA (factors: Group and Minute/Time) to access differences in behavioral profiles over time. All data is represented as Mean±SEM. While there was no difference between groups for any parameters assessed globally by U-test, the two-way ANOVA test revealed significant Group and Minute effects without interaction: (F(6)=2.36, p<0.05 Group, F(24)=3.01, p<0.001, Minute). Interestingly, the observed effect can be described as a slow reduction of escape activity in control group (27.033±12.33 s Min 1 vs. 11.83±9.68 s Min 5 for time spent near wall) that is absent in fluoxetine-treated group (27.07±8.27 vs. 25.43±17.25). Thus, the inescapable electric shock exposure produces phenotype that can be plausibly associated with despair-like behavior in zebrafish. Interestingly, habituation with decrease in activity among test was reduced by antidepressant exposure, similar to results in known rodent 'despair' tests, such as the Tail Suspension and the Forced Swim Test. Clearly, further studies are needed to replicate and better understand the observed effects in zebrafish models.
Original languageEnglish
Pages8
Publication statusPublished - 9 Sep 2018
Event15th International Regional (Asia) ISBS Neuroscience and Biological Psychiatry “Stress and Behavior” Conference -
Duration: 9 Sep 201810 Sep 2018

Conference

Conference15th International Regional (Asia) ISBS Neuroscience and Biological Psychiatry “Stress and Behavior” Conference
CountryJapan
Period9/09/1810/09/18

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