The Neurophysiology of Acupuncture: A Viewpoint

Abstract

SummaryAcupuncture is a specialised sensory stimulation that is analysed through sensory neural pathways Therefote to understand its action we have to analyse the anatomv physiology and pharmacology of the nerious system, aided with a knowledge ot' neuroendocrinology and the chemoarchitecture of the brain. Various neural theories have been developed to explain the mechanisms of acupuncturc. lt is now evident that acupuncture reacts at local, regional (spinal cord) and Seneral (brain) levels. Thetefore, inserting one or more needles at particulat poitlts (or areas) of the body actlvates neural pathways on three different levels, ptovoking local, re7ional, and Eeneral reactionsThe local reaction is a multifactorial phenomenon. The electric injury potential due to the needle, the presence and synthesis of opioid peptides at the site of injury, and substance P, histamine like subsknces, badikinin, serctonin and prcteolitic enzyme release around the needle, alloccur during needlinS.The reg,ional reaction concens the activation of a larger area (2 3 dermatomes) via reflex arches. we can analyse the viscero-cutaneous, cutaneo-visceral, cutaneo-muscular and viscero-muscular reflexes and also the vegetative, stretch and polysynaptic segmental rcflexes.The general reaction mainly activates the brain cenlral mechanism of internal homoeostasis we can explain the action ol acupuncturc ln acute and chtonic pain syndromes, in addiction and in psychiatric disease throu7h the role of central neurotransmitters and the modulatory systems that are activatecl by acupoints: opioid, non-opioid and central sympathetic inhibitory mechanisms.

Randomised, Controlled Study of Preoperative Eletroacupuncture for Postoperative Pain Control after Cardiac Surgery

“…Low-frequency EA can generate long-standing analgesia. 3 An increase in the messenger RNA for pro-enkephalin in brain (pituitary) is observed for 24-48 h following acupuncture. 3 General analgesic action is seen with the use of low frequencies and local analgesic action by the use of high frequencies.…”

“…3 An increase in the messenger RNA for pro-enkephalin in brain (pituitary) is observed for 24-48 h following acupuncture. 3 General analgesic action is seen with the use of low frequencies and local analgesic action by the use of high frequencies. 21 Higher frequencies were not http://aim.bmj.com/ used as they release dynorphin, which has rapid starting effect but much leakage, 3 14 and may reduce mesencephalic production of encephalin.…”

“…Sensitisation of the central nervous system increases as a result of segmental and suprasegmental reorganisation. [1][2][3] Postoperative pain can be regarded as inevitable because of intense surgical trauma, but if not controlled can cause several clinical risks such as atelectasis, venous thrombosis and elevated blood glucose levels with increased risk of infection, as well as cardiac risks such as higher blood pressure with increased left ventricle afterload and increased myocardial oxygen consumption. 1 2 Multiple nociceptive stimulants occur in thoracotomy procedures such as surgical incision, insertion of chest tubes and mediastinal and parietal pleura stimulation, making the provision of analgesia quite complex and requiring a combination of techniques and medication.…”

Superficial versus Deep Dry Needling

“…The needle-induced stimulation of the Aδ nerves is both an immediate one, and one lasting several hours, perhaps due to the setting up of a tissue injury-induced galvanic current. 14 …”

Narrative Review of Perioperative Acupuncture for Clinicians

“…Based upon the results of multiple scientific studies, various theories on the analgesic mechanism of action have been concluded. Such theories include the release of endogenous opioids such as beta-endorphins, stimulation of descending antinociceptive pathways, release of inhibitory neurotransmitters such as norepinephrine and serotonin, modulation of the hypothalamic-limbic system, activation of the pain neuromatrix, and a placebo effect [2,4,8,10,11]. However, the mechanisms of these actions are yet to be fully identified and understood.…”