Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve
SUMMARY: This study looked at the effect of Lactobacillus rhamnosus on GABA receptors in the brain as well as the role of the vagus nerve in communicating between the gut and the brain. Results showed that L. rhamnosus decreased cortisone levels in stressed out mice (the researchers put mice in stressful situations) and also changed the expression of GABA receptors. Due to GABA having multiple functions, GABA receptors in different parts of the brain have different functions and effects on the mice. Researchers in this study looked at mRNA of the GABA receptor proteins to determine whether or not they were being upregulated or downregulated. Finally, researchers observed that L. rhamnosus did not affect mice behavior when vagotomies were performed (cutting the vagus nerve). This implicates that the vagus nerve is partially responsible for sending messages from the gut to the brain. The animals used in this study were healthy animals, not germ-free or ones that had been treated with antibiotics.
LESSON COMMENTS: Topics that are covered in this article include: protein synthesis, neurotransmitters, action potential, neurotransmitter receptors, receptor and ligand, cortisone and how hormones are produced to maintain homeostasis, function of the different parts of the brain. This is a good article for students to read/understand (I would suggest teachers summarize the results for the students and highlight certain passages) after learning about the process of protein synthesis so they can see how knowing a process can help researchers collect data.
Bravo, J. A., Forsythe, P., Chew, M. V., Escaravage, E., Savignac, H. M., Dinan, T. G., . . . Cryan, J. F. (2011). Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proceedings of the National Academy of Sciences,108(38), 16050-16055. doi:10.1073/pnas.1102999108