How does Acupuncture Work ?
1.Modern concept – Gates at Spinal Cord
Acupuncture needles are inserted at particular point or areas expecting desired effect. Modern research has shown that very act of insertion of needle in the body stimulates connective tissue, nerve ending, peri-osteum and other tissues resulting into variety of reactions. The stimulation causes to body to release number of neuro-hormones which helps body to heal itself and relive pain. Stimulation of certain nerve fibres causes spinal cord acting as gate, to block pain stimulus which would have forwarded to brain.
As per following figure acupuncture acts on descending pathway of hypothalamus blocking perception of pain passing through spinal cord.
Pathway of Perception of Pain
Three types of nerves namely are involved in perception of tissue damage – pain. A-Beta fibres are large diameter myelinated fibres, A-Delta fibres are small diameter myelinated Fibre and C fibres are small diameter unmyelinated fibres. A-Delta fibres are responsible for accurate localization of pain and are without emotional accompaniment. Stimulation A- Delta fibres on insertion of acupuncture needle, sends its sense of stimulating activity to hypothalamus, which stimulates inhibitory system of brain stem. The brain stem system involving serotonin and noradrenalin ultimately act on SG cells in posterior horn of spinal cord where pain pathway is blocked. Thus acupuncture act on descending pathway of hypothalamus blocking perception of pain passing through spinal cord.
2. Limbic System
Cingulate Gyrus, hippocampus, amygdale and part of hypothalamus and thalamus form limbic system. It is connected with cerebral cortex and responsible for modulation of pain perception emotion and formation of memory. Since patients undergoing acupuncture frequently experience relaxation, euphoria or may laugh or cry; it possible that effect is due to its effect on Cingulate Gyrus which also modulates pain, thus we have reduced perception of pain.
3.Role of Neuro transmitters
There are three classes of opioids in analgesia – enkephalins, bet-endorphin and dynorphin. Low frequency electro-acupuncture stimulate brain and spinal cord to release of enkephalins, bet-endorphin. High frequency electro-acupuncture stimulation stimulates release of dynorphin in spinal cord. These opioids along with serotonin and oxytocin may be responsible for acupuncture analgesia. Thus stimulation distant part of body has effect on Brain as seen from above facts.