Anxiolytic effects of fluoxetine and nicotine exposure on exploratory behavior in zebrafish

Zebrafish (Danio rerio) have emerged as a popular model for studying the pharmacology and behavior of anxiety. While there have been numerous studies documenting the anxiolytic and anxiogenic effects of common drugs in zebrafish, many do not report or test for behavioral differences between the sexes. Previous studies have indicated that males and females differ in their baseline level of anxiety. In this study, we test for a sex interaction with fluoxetine and nicotine. We exposed fish to system water (control), 10 mg/L fluoxetine, or 1 mg/L nicotine for three minutes prior to being subjected to four minutes in an open-field drop test. Video recordings were tracked using ProAnalyst. Fish from both drug treatments reduced swimming speed, increased vertical position, and increased use of the top half of the open field when compared with the control, though fluoxetine had a larger effect on depth related behaviors while nicotine mostly affected swimming speed. A significant sex effect was observed where females swam at a slower and more constant speed than males, however neither drug produced a sex-dependent response.</jats:p

The quantitative genetic architecture of the bold-shy continuum in zebrafish, Danio rerio.

In studies of consistent individual differences (personality) along the bold-shy continuum, a pattern of behavioral correlations frequently emerges: individuals towards the bold end of the continuum are more likely to utilize risky habitat, approach potential predators, and feed under risky conditions. Here, we address the hypothesis that observed phenotypic correlations among component behaviors of the bold-shy continuum are a result of underlying genetic correlations (quantitative genetic architecture). We used a replicated three-generation pedigree of zebrafish (Danio rerio) to study three putative components of the bold-shy continuum: horizontal position, swim level, and feeding latency. We detected significant narrow-sense heritabilities as well as significant genetic and phenotypic correlations among all three behaviors, such that fish selected for swimming at the front of the tank swam closer to the observer, swam higher in the water column, and fed more quickly than fish selected for swimming at the back of the tank. Further, the lines varied in their initial open field behavior (swim level and activity level). The quantitative genetic architecture of the bold-shy continuum indicates that the multivariate behavioral phenotype characteristic of a "bold" personality type may be a result of correlated evolution via underlying genetic correlations

Ancient and recent duplications of the rainbow trout Wilms' tumor gene

The Wilms' tumor suppressor (WT1) gene plays an important role in the development and functioning of the genitourinary system, and mutations in this gene are associated with nephroblastoma formation in humans. Rainbow trout (Oncorhynchus mykiss) is one of the rare animal models that readily form nephroblastomas, yet trout express three distinct WT1 genes, one of which is duplicated and inherited tetrasomically. Sequence analyses suggest an ancient gene duplication in the common ancestor of bony fishes resulted in the formation of two WT1 gene families, that conserve the splicing variations of tetrapod WT1, and a second duplication event occurred in the trout lineage. The WT1 genes of one family map to linkage groups 6 and 27 in the trout genome map. Reverse transcribed polymerase chain reaction (RT-PCR) expression analysis demonstrated little difference in WT1 tissue expression pattern between genes.Key words: tumor suppressor, nephroblastoma, RT-PCR expression, kidney, cancer, cDNA, gene mapping.</jats:p

Anxiolytic effects of fluoxetine and nicotine exposure on exploratory behavior in zebrafish

Zebrafish (Danio rerio) have emerged as a popular model for studying the pharmacology and behavior of anxiety. While there have been numerous studies documenting the anxiolytic and anxiogenic effects of common drugs in zebrafish, many do not report or test for behavioral differences between the sexes. Previous studies have indicated that males and females differ in their baseline level of anxiety. In this study, we test for a sex interaction with fluoxetine and nicotine. We exposed fish to system water (control), 10 mg/L fluoxetine, or 1 mg/L nicotine for three minutes prior to being subjected to four minutes in an open-field drop test. Video recordings were tracked using ProAnalyst. Fish from both drug treatments reduced swimming speed, increased vertical position, and increased use of the top half of the open field when compared with the control, though fluoxetine had a larger effect on depth related behaviors while nicotine mostly affected swimming speed. a significant sex effect was observed where females swam at a slower and more constant speed than males, however neither drug produced a sex-dependent response.</jats:p

Anxiolytic effects of fluoxetine and nicotine exposure on exploratory behavior in zebrafish

Zebrafish (Danio rerio) have emerged as a popular model for studying pharmacological effects on behavior and anxiety. While there have been numerous studies documenting the anxiolytic and anxiogenic effects of common drugs in zebrafish, many do not report or test for behavioral differences between the sexes. Previous studies of zebrafish have indicated that males and females differ in their behavioral responses to anxiety. In this study, we test for sex-dependent effects of fluoxetine and nicotine. We exposed fish to system water (control), 10 mg/L fluoxetine, or 1 mg/L nicotine for three minutes prior to being subjected to four minutes in an open-field drop test. Video recordings were tracked using ProAnalyst. Fish from both drug treatments reduced swimming speed, increased vertical position, and increased use of the top half of the open field when compared with the control, though fluoxetine had a larger effect on depth related behaviors while nicotine mostly affected swimming speed. A significant sex effect was observed where females swam at a slower and more constant speed than males in all treatments. No interactions between sex and the drugs were observed across the entire study.</jats:p

Response of Swim Level and Feeding Latency to selection on horizontal position in zebrafish.

<p>Replicate 1 (A & C), Replicate 2 (B & D). P = unselected parental generation (gray circle), 1 = first generation progeny from selected parents, 2 = second generation progeny from selected parents. Black diamonds with a solid line represent means ± SE of High line fish, open squares with a dashed line represent means ± SE of Low line fish. “*” indicate significant (p<0.05) differences between lines within a generation using a mixed-model ANOVA.</p