Relating Gene Expression to Neurophysiological Response of Wild Caught Yellow Perch Under Short and Long Term Metal Exposure

Aquatic organisms, such as fish, mediate vital processes using their sense of smell, or olfaction. Numerous lab studies have shown that exposing fish to low concentrations of contaminants, including metals, can disrupt chemical communication. Fewer studies, however, have investigated contaminant-induced olfactory toxicity using wild fish. For this study we employed two techniques, a microarray analysis of olfactory tissue utilizing a novel yellow perch (Perca flavescens) microarray, and electro-olfactography (EOG), which measures olfactory acuity. The transcriptional and EOG response of yellow perch from clean and contaminated lakes in the industrial region of Sudbury, ON, were compared. The results demonstrate that fish from a clean lake have a greater olfactory acuity than those from metal contaminated lakes, and there is very little difference in baseline gene expression between them. To investigate short-term exposures, fish from the clean lake were exposed for 24 h to ecologically-relevant concentrations of nickel or copper, or to water from metal contaminated lakes. Both experimental methods showed a reduction in olfactory acuity. These results are relatable to the gene expression profiles measured for fish given copper or nickel exposures. Taken together, this work is the first to connect the gene expression of wild-caught fish with neruophysiological responses.