Acupuncture Explained
TELL ME MORE - SEGMENTAL EFFECT
For the full "Acupuncture Explained" article >>> see here
There are two effects at the segmental level. Pain inhibition and a reflex effect that affects the tone of skin, muscle and viscera related to that level of the spinal cord.
Inhibition. Both C fibres and A fibres enter the spinal cord at the dorsal horn, an area of grey matter that we can see in cross section. After entering the dorsal horn the C fibre neuron synapses with an intermediate neuron (in substantia gelatinosa), which in turn synapses with a neuron in an ascending tract that rises to the thalamus at the base of the brain. The ergo-receptors that we stimulate by manipulating the needle generate afferent input via Aδ fibres that inhibit the intermediate neuron between the C fibre and the ascending tract, thereby reducing the intensity of the incoming pain signals. This phenomenon is similar to the “pain gate” model proposed by Melzack and Wall in 1965.
The stimulation also creates a reflex response that causes increased sympathetic tone in all the tissues that are innervated from this level. This includes the skin, muscle, connective tissue and even visceral organs.
Take the gut for example: a few minutes of acupuncture (abdominal wall segmental) will inhibit the activity of the gut by raising sympathetic tone; useful for treating diarrhoea. However, if stimulation is longer, say 20min there is a different response, the initial increase in sympathetic tone is followed by a decrease in tone that will last up to 18 hours. This can help with constipation. These long-term effects are dependent on the central control system 51 that affect the sympathetic activity at the lower level.
START HERE - read the articles in this order
>>> ACUPUNCTURE EXPLAINED
>>> Acupuncture Explained - Tell me more - Local Effect
>>> Acupuncture Explained - Tell me more - Segmental Effect
>>> Acupuncture Explained - Tell me more - General Effect
>>> Acupuncture Explained - Tell me more - Trials, Placebo and Sham Acupuncture
Bill Ferguson, Osteopath
May 2020
