6-hydroxydopamine is a dopamine analogue that selectively destroys dopaminergic neurons. It is used in biomedical research to destroy the substantia nigra in lab animals and induce Parkinson’s-like symptoms.
Choi et al. were interested in studying the early stages of Parkinson’s disease. Before the onset of motor symptoms, patients suffer from poor gastric emptying and constipation. Previous research suggests that Parkinson’s disease is also associated with changes in gut microbiome. Choi et al. sought to test whether Parkinson’s-like brain lesions directly caused changes in gut microbiome.
To test this, they injected 6-hydroxydopamine into mice. Two weeks later, they collected fecal samples from the mice, then extracted and sequenced 16S rRNA to identify microbial species.
Injected mice and control mice had about the same microbial species richness in their feces, but species composition changed. Injected mice contained fewer bacteria from the genus Lactobacillus and more from the genus Bacteroides. The researchers suggest that the Parkinson’s-lesioned brain might affect gut microbia through changes in the firing of the vagus nerve.
Choi JG, Huh E, Kim N, Kim D-H, Oh MS (2019). High-throughput 16S rRNA gene sequencing reveals that 6-hydroxydopamine affects gut microbial environment. PLoS ONE 14(8): e0217194. https://doi.org/10.