Faculty Scholarly Dissemination Grants

Title

Methylmercury Exposure Produced Learning Impairments More Severely in Old Adult than in Young Adult Zebrafish

Department

Psychology

College

College of Liberal Arts and Sciences

Date Range

2011-2012

Abstract

Zebrafish has become a useful organism for studying the neurobehavioral effects of environmental contaminants throughtout the life-span of an organism due to its short generation times, high numbers of eggs per female, and ease of breeding. The present study compared the effects of methylmercury exposure in old adult zebrafish against young adult zebrafish using avoidance conditioning as the behavioral paradigm. In Experiment 1, old adult zebrafish were exposed to no methylmercury, ethanol, 0.01, 0.03, 0.1, or 0.3 µM of methylmercury for two weeks. Fish were then trained and tested for avoidance responses. The results showed that old adult zebrafish exposed to no methylmercury or ethanol learned and retained avoidance responses. However, 0.01 µM or higher concentrations of methylmercury exposure impaired avoidance learning in a dose-dependent manner with 0.3 µM of methylmercury exposure producing death during the exposure period or shortly after the exposure before behavior testing. In Experiment 2, young adult zebrafish were exposed to no methylmercury, ethanol, or the same various concentrations of methylmercury used in Experiment 1 for two weeks. Fish were then trained and tested for avoidance responses. The results showed that young adult zebrafish exposed to no methylmercury, ethanol, 0.01, or 0.03 µM of methylmercury learned and retained avoidance responses, while 0.1 or 0.3 µM of methylmercury exposure impaired avoidance learning in dose-dependent manner in young adult zebrafish. The study suggested that methylmercury exposure produced learning impairments at a much lower concentration of methylmercury exposure and more severely in old adult compared against young adult zebrafish.

Conference Name

Annual Meeting of Society for Neuroscience

Conference Location

Washington, DC

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