The enteric nervous system: “A little brain in the gut”
Based largely on results from preclinical studies, the concept of a brain gut microbiome axis has been established, mediating bidirectional communication between the gut, its microbiome, and the nervous system. Limited data obtained in human beings suggest that alterations in these interactions may play a role in several brain gut disorders.
1 of 6: the gut-brain axis:
|
|
The gut brain axis describes the complex interaction between the brain, the enteric nervous system in the gut and the microbiome.
|
2 of 6: our Microbiome and our Brain
|
|
There are trillions of microbes inside us, we are learning that these little creatures may have significant influence on our brains.
|
3 of 6: the gut brain axis
4 of 6 : UPENN VET shows how a parasite gets past the blood-brain barrier
5 of 6 : understanding the blood-brain barrier
6 0f 6 : Functional anatomy of gut-brain communication and the ENS:
Panel B above illustrates the myenteric and submucous plexus layers of the ENS in the gut wall.
Image Source : Prof. Simon Brookes, Flinders University, Adelaide, Australia.
Citation: Neuroforum 26, 1; 10.1515/nf-2019-0027 |
Fascinating new research tells us that our gut exerts an influence on the brain, affecting our mood, hormonal balance and obesity levels.
Researchers from Penn’s School of Veterinary Medicine using a powerful imaging technique ( called multiphoton microscopy ) that allowed scientists to track the presence and movement of parasites in living tissues. ( Researchers found that Toxoplasma infects the brain’s endothelial cells, which line blood vessels, reproduces inside of them, and then moves on to invade the central nervous system).
Crossing the blood-brain barrier is a rare event in part because this structure is designed to protect the brain from pathogens. And yet it happens and we have now been able to visualize these events. It’s something that no one had seen before. The blood-brain barrier (A.K.A BBB) protects the brain from infection, but also on the flip side.. prevents medicines from entering.
SIDE NOTE: Scientists are developing methods for sneaking medicines past the barrier by exploiting the "transferrin pathway" too! Panel A (image to the left) is a simplified scheme to demonstrate control of gut functions at different levels. The most relevant is the ENS, which controls gut functions independent of extrinsic inputs. Nevertheless, the gut is connected to the brain via nerves which function as the gut-brain axis – sensory neurons with cell bodies in dorsal root ganglia or in parasympathetic relay ganglia, e. g. nodose ganglion, and efferent nerves of the parasympathetic and sympathetic nervous systems. Note that there is no region in the brain exclusively dedicated to gut functions. |