You pick up the telephone to call your best friend. You dial a number which will, in effect, let the phone know where to send the signals. But unbeknownst to you, something has worn away the rubber which covers and protects the wires within your phone. Some signals cannot get through, and the ones that do are ambiguous. As a result your important information does not get conveyed to your friend.
This is a circumstance similar to the process that occurs within the body of a person with Multiple Sclerosis, a disease of the spinal cord and brain which affects over 300,000 Americans. The onset of Multiple Sclerosis, or MS, usually occurs between the ages of 22 to 33 years of age and most frequently affects women between the ages of 30 and 50.(1) Yet Multiple Sclerosis is one of the few neurological diseases which is characterized by remission (the disappearance of symptoms for an extended period of time.) As a result, it is likely that scientists will be able to discover therapies for the disease because if they are able to figure out how and why the remission of Multiple Sclerosis occurs, they might be able to force the body into a state of constant remission.
Transmitting Signals: A Look at the Nervous System
Before taking a closer look at Multiple Sclerosis, it is important to understand the body's nervous system, which is composed of the central and peripheral nervous systems. The central nervous system, which is made of the brain and the spinal cord, is responsible for the integration of information. The peripheral nervous system, which is constituted by all additional nerve cells not in the central nervous system, is responsible for conveying information to and away from the central nervous system to various parts of the body.
Neurons, or the units of nerve cells, have extremely complex structures to assure maximum efficiency in transmitting information. Each neuron has a large cell body which contains the nucleus of the cell as well as other cellular organelles which help with maintenance functions of the cell. Dendrites, or fiber-like extensions which increase the surface area of the cell to increase effectiveness, receive information from other cells. Axons are larger extensions of the cell which transmit information away from the cell body towards other cells.
Each axon is enclosed by a chain of cells called Schwann cells which support the neuron. While these cells do not function in transmitting sensory information, they support the cells structurally and by controlling the passage of substances into the cells. Together these cells form an insulating layer around the neurons called the myelin sheath.
This myelin sheath is similar to the rubber which coats the wires of your telephone. Yet in a person with Multiple Sclerosis, the immune system mistakenly identifies some component of myelin as a foreign agent, or antigen. This elicits an auto-immune response in which the body attacks and slowly...