Title
The effect of phenylpropanolamine on the development of the lateral line system, heart rate, and morphology of Danio rerio larvae by Cassie Olson
Description
Phenylpropanolamine (PPA) is a sympathomimetic drug that is a vasoconstrictor and bronchodilator. In 2000, it was removed from the market due to causing stroke. Research on a relationship between PPA exposure and hair cell development has not yet been observed. The zebrafish (Danio rerio) is a useful model for studying ototoxic effects on hair cells because the lateral line system along the outside of their body is composed of hair cells. Ototoxic effects on the hair cells of the lateral line system can help determine ototoxic effects on the hair cells of the inner ear of mammals and humans. The lateral line system is a mechanosensory organ that senses water flow. When stimulated in zebrafish larvae an escape response is evoked. Using this knowledge, tests were done to stimulate lateral line and determine if there was a difference in the reaction times of larvae which developed in various concentrations of PPA ranging from 0.25 to 1.5 mM until 5 days post fertilization (dpf). Additionally, photos were taken and heart rate was observed after incubation in PPA and after over-night recovery. Reaction time results were determined to be inconclusive. However, heart rate results showed that there was a significant decrease in the heart rate of larvae treated with 0.50 and 0.75 mM PPA until 5dpf. After recovery, larvae treated with 0.25 and 0.50 mM PPA experienced a significant increase in heart rate which was not significantly different from the control. Differences in morphology were observed among concentration groups.