| Title: | Chronic Exposure to Oxazepam Pollution Produces Tolerance to Anxiolytic Effects in Zebrafish (Danio rerio) |
| Author(s): | Vossen LE; Cerveny D; Osterkrans M; Thornqvist PO; Jutfelt F; Fick J; Brodin T; Winberg S; |
| Address: | "Department of Neuroscience , Uppsala University , SE-751 24 Uppsala , Sweden. Department of Chemistry , Umea University , SE-901 87 Umea , Sweden. Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses , University of South Bohemia in Ceske Budejovice , Zatisi 728/II , 389 25 Vodnany , Czech Republic. Department of Biology , Norwegian University of Science and Technology , EU2-167 Trondheim , Norway. Department of Wildlife, Fish and Environmental Studies , Swedish University of Agricultural Sciences , SE-901 83 Umea , Sweden" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "Environmental concentrations of the anxiolytic drug oxazepam have been found to disrupt antipredator behaviors of wild fish. Most experiments exposed fish for a week, while evidence from mammals suggests that chronic exposure to therapeutic concentrations of benzodiazepines (such as oxazepam) results in the development of tolerance to the anxiolytic effects. If tolerance can also develop in response to the low concentrations found in the aquatic environment, it could mitigate the negative effects of oxazepam pollution. In the current study, we exposed wild-caught zebrafish to oxazepam ( approximately 7 mug L(-1)) for 7 or 28 days and evaluated behavioral and physiological parameters at both time points. Females showed reduced diving responses to conspecific alarm pheromone after 7 days, but not after 28 days, indicating that they had developed tolerance to the anxiolytic effects of the drug. Zebrafish males were not affected by this oxazepam concentration, in line with earlier results. Serotonin turnover (ratio 5-HIAA/5-HT) was reduced in exposed females and males after 28 days, indicating that brain neurochemistry had not normalized. Post-confinement cortisol concentrations and gene expression of corticotropin-releasing hormone (CRH) were not affected by oxazepam. We did not find evidence that chronically exposed fish had altered relative expression of GABA(A) receptor subunits, suggesting that some other still unknown mechanism caused the developed tolerance" |
| Keywords: | "Animals *Anti-Anxiety Agents Environmental Pollution Female Male Oxazepam *Water Pollutants, Chemical Zebrafish;" |
| Notes: | "MedlineVossen, Laura E Cerveny, Daniel Osterkrans, Marcus Thornqvist, Per-Ove Jutfelt, Fredrik Fick, Jerker Brodin, Tomas Winberg, Svante eng Research Support, Non-U.S. Gov't 2020/01/15 Environ Sci Technol. 2020 Feb 4; 54(3):1760-1769. doi: 10.1021/acs.est.9b06052. Epub 2020 Jan 24" |
