The Effect of Theophylline on Anxiety in Zebrafish (Danio rerio) Megan Conahan* and Dr. Wendy Boehmler Department of Biological Sciences, York College of Pennsylvania Introduction  A 1 and A 2A antagonists have been found to be protective against neurodegenerative diseases. Compounds that have this property are considered neuroprotective.  Methylxanthines, such as caffeine and theophylline are nonselective antagonists of the A 1 and A 2A adenosine receptors (Fredholm et al. 1999).  Blockade of these receptors has been associated with reduced risk of Alzheimer’s disease and Parkinson’s disease.  Both, theophylline and caffeine have been linked to reduced risk of Parkinson’s disease (Xu et al. 2010). Caffeine has also been found to reduce the risk of Alzheimer’s disease (Dall’Igna et al. 2003)  Caffeine has been found to cause increased anxiety levels by many different studies (Egan et al. 2009). This is an unwanted side effect, suggesting a potential drawback in using caffeine as a neuroprotective agent.  The effect of theophylline on anxiety has been studied very little. It was found in mice that theophylline had a much less potent effect on anxiety (Lopez-Cruz 2014). This suggests that theophylline could be a potential alternative neuroprotective agent.  Zebrafish are increasingly being used as a behavioral model organism, specifically in the field of stress and anxiety. They have also been used to study: social behavior, addiction, sleep, learning and memory. Using zebrafish as a model for these behavioral tests has made them a good candidate for accelerated drug discovery. Other advantages of using zebrafish as a model system include, that they are inexpensive and easy to house in large numbers. Hypothesis We predicted that theophylline would increase anxiety in zebrafish, but, have a weaker effect when compared to caffeine making theophylline an alternative neuroprotective agent to caffeine. Methods Pre-treatment (n=10) 10 minutes 40 zebrafish Pre-treatment of plain tank water (Negative Control) 0.5 mM Caffeine (Positive Control) 0.5 mM Theophylline (Low Dose) 5.0 mM Theophylline (High Dose) Acclimation Time (2 minutes) Behavioral Testing (5 minutes) Results Conclusions Caffeine significantly increased anxiety levels compared to theophylline The low dose and high dose of theophylline produced significantly less anxiety than caffeine This suggests that theophylline would be a good alternative neuroprotective agent when compared to caffeine Due to the high through put potential of this model system, it will be of great interest to continue to identify and test candidate drugs that can be used as neuroprotective agents. Literature Cited Dall’Igna, O.P., Porciuncula, L.O., Souza, D.O., Cunha, R.A., Lara, D.R Neuroprotection by caffeine and adenosine A2A receptor blockade of β-amyloid neurotoxicity. British Journal of Pharmacology. 138: Egan, R.J., Bergner, C.L., Hart, P.C., Cachat, J.M., Canavello, P.R., Elegante, M.F., Elkhaya, S.I., Bartels, B.K., Tien, A.K., Tien, D.H, Mohnot, S., Beeson, E., Glasgow, E., Amri, H., Zukowska, Z. Kalueff, A.V Understnading behavioral and physiological phenotypes of stress and anxiety in zebrafish. Behavioural Brain Research. 205: Fredholm, B.B., Battig, K., Holmen, J., Nehlig, A., Zvartau, E.E Actions of Caffeine in the Brain with Special Reference to Factors That Contribute to Its Widespread Use. Pharmacological Reviews. 51: Lopez-Cruz, L., Pardo, M., Salamone, J.D., Correa, M Differences between the nonselective adenosine receptor antagonists caffeine and theophylline in motor and mood effects: Studies using medium to high doses in animal models. Behavioural Brain Research. 270: Xu, K., Xu,Y.H., Chen, J.F., Schwarzschild, M.A Neuroprotection by caffeine: Time course and role of its metabolites in the MPTP model of Parkinson Disease. Neuroscience. 167: Acknowledgements I would like to thank Dr. Wendy Boehmler and Dr. Bridgette Hagerty for their assistance and advice throughout this project. *This was a blind study (Egan et al. 2009)