Friday, July 18, 2014

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.

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 form the central nervous system – connects the central nervous system to limbs and organs.

In this study, the researchers say their findings may change the current understanding of how the peripheral nervous system is formed.

Using 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.
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 that 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 the Schwann cell precursors create the entire parasympathetic nervous system. “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,” say Adameyko and Ernfors.

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

Think of the parasympathetic nervous system as slowing down everything but digestion, which it speeds up. The urban myth about not swimming for an hour after you eat has some validity as the parasympathetic nervous system shuts blood from the extremities to the digestive tract to support digestion after eating. It is that aspect of the autonomic (think automatic) nervous system that is calming, sedative, and tranquil.

The Cells of Schwann, when mature, are attached to the peripheral nervous system at regular intervals, invested in the myelin sheath that covers and protects the nerves. These cells orchestrate repair and regeneration of the peripheral nervous system. The central nervous system is void of both the Cells of Schwann and the myelin sheath covering; so damage to the central nervous system is permanent. This is why Christopher Reeves’ spinal cord injury was eventually fatal – the central nervous system was badly damaged and could not regenerate.

Unfortunately, new drug development is what drives most medical research. I suggest that this new information would be more useful in developing methodology to create progenitor Schwann cells from stem cells. These progenitor cells could then be used to help regenerate nerves in amputees and maybe even treat spinal cord injuries.

When you read research like this, think of potential uses beyond another drug that will make the drug manufacturer a ton of money. That’s where the future of health care must lie.

Source: Medical News Today –Monday, June 16, 2014