Faculty Mentor(s)

Dr. Erika Calvo-Ochoa, Biology

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Exposure to hypoxic conditions leads to neural loss of function or death in the nervous system of mammals. Zebrafish, given their sophisticated neuroregenerative abilities, are able to survive low-oxygen conditions with fewer consequences. These capabilities are crucial for the olfactory system of zebrafish, as their olfactory epithelium is directly exposed to damage and toxins in the environment. Given that olfaction allows for critical behaviors such as foraging, mating, predator detection, and non-visual perception of dead fish, possessing functional olfactory sensation is vital to survival. Cadaverine is a chemical compound that mimics putrescine, the scent of decaying flesh. This scent induces an anxiety response in zebrafish, observed through behaviors such as sudden rapid movements followed by freezing, sinking, and decreased exploration. By experimentally causing these behaviors, it is possible to determine the extent of olfactory function following hypoxic treatment. Our objective was to understand whether hypoxia affects olfactory-induced anxiety behaviors in adult zebrafish. We examined this through two aims: first, whether hypoxia decreases the amount of time the fish exhibited the freezing/sinking anxiety response. Second, how much time the fish spent in the lower third of the behavioral tank (i.e., decrease in exploratory behavior). Our hypoxia group was exposed to 0.6-0.8 mg/dL of dissolved oxygen (DO) levels for 15 minutes, whereas control fish were exposed to normal OD levels of 5-7 mg/dL the day before exposure to cadaverine. We recorded behavioral responses for 30 seconds before and after exposure. Our preliminary results suggest that hypoxia reduced olfaction in adult zebrafish due to a decrease in anxiety responses, as well as decreased time spent exploring. Implications of this study could lead to further research on human anxiety, as well as other olfactory methods that may be used to treat anxiety in humans without hypoxic exposure.


This research was supported by the Neuroscience Program and Biology Department at Hope College.

Title on poster differs from abstract booklet. Poster title: Olfactory-Induced Anxiety Behaviors Following Hypoxia in Adult Zebrafish