Meeting Abstract
The sensory unit of the lateral line system of fishes is the neuromast, an organ containing hair cells that detect mechanical stimuli in the environment. This mechanosensory system contributes significantly to food acquisition, predator avoidance, navigation and social interactions in different fish species. Lacking functional eyes, Mexican cave fish (Astyanax mexicanus) have a particularly well-developed lateral line system. The superficial disposition of neuromasts affords ready exposure to water borne chemical agents. For example, homology between lateral line hair cells and mammalian inner ear hair cells has led to use of cave fish as a model system in chemical ototoxicity studies. Rotenone is a plant-derived insecticide and piscicide that acts as a mitochondrial electron transport inhibitor; it is widely used in insect control and fish population management. In mammals, directed oxidative damage to dopaminergic neurons suggests a link between low levels of rotenone exposure and Parkinson’s disease. This study examines the effects of sub-lethal rotenone treatment on the neuromasts of the cave fish. Treatment groups were exposed to either low volumes of vehicle ethanol (controls) or 0.1 mg/L rotenone for up to 18 hours. Fish were then stained with the fluorescent mitochondrial marker DASPEI and neuromasts were imaged using fluorescence microscopy. Analysis of results focuses on comparisons of location-specific counts of neuromasts and assessment of hair cell integrity. I predict that increased time of rotenone treatment will be associated with a decrease in the number of viable neuromasts. Results of this work may contribute to a better appreciation of the physiological and cellular consequences associated with exposure to low levels of rotenone in an aquatic vertebrate.
