Axon reflex

Reflexes are single reactions that respond to a stimulus making up the building blocks of the overall signaling in the body's nervous system.

In 1890 the British physiologist, John Neuport Langley, researched the hair movement on cats as they were exposed to cold temperature.

In the early 20th century, British cardiologist Sir Thomas Lewis researched mechanical abrasion to the skin.

Lewis believed that the skin’s response was due to the dilation of neighboring blood vessels that were triggered by the nervous system through the axon reflex.

This response is similar to Lewis’s research with vasodilation as both rely on an intact sensory nerve supply that affect neighboring tissues.

[5] At the end of the 20th century more sophisticated methods for direct observation of the axon reflex arose due to more precise imaging tools and more advanced techniques.

These research techniques have helped to improve medical treatment and prevention of cold-related skin damage and frostbite injuries.

The compound capsaicin can be used to deplete the chemicals in the axon reflex nerve endings and reduce the symptoms of itching and pain.

Examples of axon reflex mediated mechanisms include itching, inflammation, pain, asthma, and dermal circulation.

[5] The body responds to multiple types of trauma including infection, physical injury, or toxic tissue damage through inflammation.

When pain sensation increases, the axon reflex stimulates (and is responsible for) to release of many necessary chemicals that promote local tissue inflammation of the traumatized region.

Axon reflex allows muscles to contract in the shortest amount of time possible by regulating the signal conduction in the neuromuscular junction.

Small nerve fibers called thermoreceptors are sensitive to temperature and can act as sensors that initiate axon reflex mediated vasodilation.

[7] Fasciculations are prominent features in amyotrophic lateral sclerosis (ALS) and could be evidence of abnormal axon reflex with further research.

[9] The skin is stimulated with electricity, causing said axon reflexes, which allows for the assessment of the type and severity of autonomic nervous disorders and peripheral neuropathies like asthma or multiple sclerosis.

[10] Heat sensitive receptors are present in the skin, viscera, and spinal cord where they receive information from the outside environment, and send it to the thermoregulatory center in the hypothalamus.

A flow map of the axon reflex. Stimulation of the axon can cause electric flow to all effector tissues the neuron innervates, as well as back to the soma of the neuron; this is distinct from a normal neuron firing only down the axon.
A normal spinal cord reflex arc, whereas the axon reflex would bypass the interneuron. This distinction is important because early researchers had to differentiate between the spinal cord reflex and the axon reflex to understand the body's response to stimuli.
Vasoconstriction and vasodilation, an effect that can be caused from axon reflex stimulation in certain tissues, demonstrated compared to the normal blood vessel.