Date of Defense

4-17-2014

Date of Graduation

4-2014

Department

Biological Sciences

First Advisor

Christine Byrd-Jacobs

Second Advisor

Christopher Pearl

Third Advisor

John Spitsbergen

Abstract

The zebrafish olfactory system is a valuable model for examining the ability of neurons to recover from damage. Previous experiments showed disruption of glomeruli and olfactory-mediated behavior when detergent is chronically applied to the olfactory organ over a period of 3 weeks, though both return with a recovery period. The aim of the current study was to examine the effects of a single detergent treatment. Olfactory organs were treated once with Triton X-100 unilaterally to study glomerular innervation patterns or bilaterally to study behavior . Fish were allowed to recover for 4 or 7 days and were compared to untreated control fish. Axonal projections were analyzed using whole mount immunohistochemistry with anti-keyhole limpet hemocyanin. Confocal imaging showed disruption of glomerular innervation patterns in the olfactory bulb at 4 days, particularly of ventral-medial and dorsal glomerular clusters. Lateral glomeruli appeared less effected. Innervation patterns returned to control levels at 7 days. Some fish were placed in a behavior tank and exposed to water or a cocktail of amino acids or bile salts; the number of turns the fish made before and after odorant delivery was compared. Control fish turned more after exposure to both odorants. Fish 4 and 7 day post-treatment made more turns in response to amino acids, but did not respond to bile salts. Our results suggest that a single detergent treatment disrupts glomeruli in the olfactory bulb and olfactory-mediated behavior. Glomeruli that were more affected tended to contain ciliated OSN projections while those containing microvillar OSN projections appeared less affected after detergent exposure. These findings highlight the plasticity of the zebrafish olfactory system, which can lose and recover entire clusters of glomeruli in a week.

Access Setting

Honors Thesis-Restricted

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