Gate Theory of Pain Ad Acupuncture

Jennifer Moser

Dr. Wilk

BIOL-3442-001

February 10, 2016

The Gate Theory of Pain and Acupuncture

Melzack and Wall sought out to understand why and how pain, or pain sensations, felt more intense or less intense depending on the circumstance. If something is expected to hurt, it will probably hurt worse. If we are in “flight or fight” mode, the pain may hurt less. Melzack and Wall proposed “the gate theory” of pain to answer this question. This theory states that there are nociceptors, or pain fibers, and touch fibers. These fibers synapse within the dorsal horn of the spinal cord and form a neurological “gate,” which is the substantia gelatinosa and T-cells. Once stimulation breeches the threshold, the pain stimulus is allowed to continue on to the brain, which causes us to feel pain, or if not, it is blocked. Pain is controlled by the activity in these fibers. Based on which type of fibers are stimulated, pain can travel faster up to the brain, or not at all. A-nerve fibers, or larger fibers, inhibit signals to the brain or “closes” the gate, while C-nerve fibers, which are smaller, “open” the gate and cause us to feel the sensation of pain.

For example, if one hits one’s knee on the corner of a desk, most of the time a person will rub or put pressure on the area that was hit. Rubbing the area can alleviate some of the pain because it interferes with or inhibits the activity of A-fibers or C-fibers. This is why massage, touching, or acupuncture may help to reduce chronic pain.

Acupuncture involves using small needles inserted in the body at “acupuncture points” usually to relieve pain. Once thought of as a pseudoscience, acupuncture is not what it used to be. In the example of rubbing the knee after it has been hit, is similar to the benefits of acupuncture. When a part of the body is in pain, the pain is transmitted by the peripheral nerves to the spinal cord and the brain. These signals responsible for pain can be overridden by...