Caffeine and taurine are common ingredients listed on the nutritional label of energy drinks. However, in many drinks, these compounds are marketed as a “specialized blends.” The consumption of energy drinks has increased in recent years, yet there is little research on neural morphology and the dosages of ingredients in these “specialized blends.” The present study investigated the relationship of varying dosages of caffeine and taurine on primary rat cortical neurons by measuring the neuronal outgrowth of primary, secondary, and tertiary neurites within each treatment and concentration condition. This evaluation included seven treatments (excluding the control group) of both caffeine (100 μM -1mM) and taurine (50 μM -2mM), cultured over two weeks. Neurons were imaged using phase-contrast microscopy and analyzed using NeuronJ. Data collected was used to establish a dose-response curve for each agent. Caffeine displayed a biphasic curve inferring two mechanisms working on neurite regulation and taurine displayed a U-shaped curve. An interaction between neurite type and concentration on neurite outgrowth was apparent [F(12, 5901) = 3.34, p = .005, η2 = .007], suggesting concentration impacts the frequency of the types of neurons, which ultimately contributes to overall neuron length. Furthermore, the main effects for treatment (p <0.001), concentration (p <0.001), and neurite type (p <0.001) on neurite outgrowth were revealed and will be discussed.

Keywords: caffeine, taurine, dose-response curve, neurite outgrowth

Wendy Teal would like to thank their faculty sponsor Dr. Alaina Baker-Nigh for their support of this project.