Study provides new insight into the formation of the nervous system

New research from the Karolinska Institutet in Sweden has revealed some interesting new findings about the formation of part of the nervous system, which they say could lead to new treatments for nervous system disorders that are present from birth.
The research team, including Igor Adameyko, of the Department of Physiology and Pharmacology, and Patrik Ernfors, of the Department of Medical Biochemistry and Biophysics, recently published their findings in the journal Science.
The nervous system consists of two parts - the central nervous system and the peripheral nervous system. The central nervous system - made up of the brain and spinal cord - is the core processing center that controls the body's activities. The peripheral nervous system - made up of nerves leading to and from the central nervous system - connects the central nervous system to limbs and organs.
In this latest study, the researchers say their findings may change the current understanding of how the peripheral nervous system is formed.
Through creating 3D reconstructions of mouse embryos, they identified how the parasympathetic nervous system develops. This is a part of the autonomic nervous system (in the peripheral nervous system) that is responsible for conserving energy as it slows the heart rate, increases glandular and intestinal activity and relaxes sphincter muscles.

Researchers say their findings may change the current understanding of how the peripheral nervous system is formed.

According to the investigators, current belief holds that in various organs, parasympathetic nerve cells first arise in early progenitor cells - early descendants of stem cells that can turn into different cell types - that travel short distances when an embryo is small.
However, the team says this belief fails to explain why many organs that develop when an embryo is larger contain cells that create parasympathetic neurons.
From close analysis of the 3D mouse embryos, they found that progenitor cells - called Schwann cell precursors - create parasympathetic neurons. These progenitor cells travel through the peripheral nerves to tissue and organs in the body.
The researchers say they were surprised to find that these Schwann cell precursors create the entire parasympathetic nervous system.
Commenting on the findings, Adameyko and Ernfors say:

"Our study focuses on a new principal of developmental biology, a targeted recruitment of cells that are probably also used in the reconstruction of tissue.
Despite the elegance, simplicity and beauty of this principal, it is still unclear how the number of parasympathetic neurons is controlled and why only some of the cells transported by nerves are transformed into that which becomes an important part of the nervous system."

The researchers note, however, that they hope their discovery will open the doors to new drug treatment for congenital disorders of the nervous system.