Locomotion and Anxiety After Caffeine Intake in HiS and LoS Rats

Document Type


Publication Date

Summer 2012


Caffeine is a widely consumed psychoactive substance, present in many types of comestibles. As a stimulant, caffeine is positively correlated with increased alertness and energy. Caffeine’s arousing effect stems from the blockage of adenosine receptors in the brain, which when blocked, increase neuron firing in the brain and adrenaline production. Caffeine also induces anxiety. During prolonged exposure to caffeine, tolerance develops as an adaptive response; however, removal of the drug may result in a state of emergency.

The present research investigated the behavioral effects of caffeine intake and withdrawal with regards to locomotor activity and anxiety in an “open field” apparatus. High-Saccharin- (HiS) and Low-Saccharin-preferring (LoS) rats were used to examine drug effects; their differential consumption of saccharin may influence drug-related behaviors. They have been shown to differ in emotionality, with LoS rats typically displaying more anxiety than HiS rats.

Results indicate that on day 1, movement in the center of the open field was lower among caffeine-treated rats. In addition, latency to enter the center was longer in caffeine-treated rats; this effect arose primarily from the test conducted after caffeine was removed, suggesting withdrawal effects. There was no significant difference in total locomotion between the “caffeine” and “control” groups, pointing to anxiety rather than reduced activity in the drug effects. Relative to HiS rats, LoS rats had shorter latencies to enter the center of the open field and were more active in the center, but the lines responded similarly to caffeine. Future research could examine whether dosage or intake method has an effect on behavior.

Creative Commons License

Creative Commons Attribution-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-No Derivative Works 3.0 License.


Nancy Dess




Howard Hughes Medical Institute Undergraduate Science Education Grant

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