The Mechanism of Acupuncture
by Charles Shang |
Morphogenesis
and the
meridian system
A modern scientific
explanation of
acupuncture points and the meridian is
important to further the study
and application of related
techniques.[1,2] According to the Standard
International
Acupuncture Nomenclature proposed by the World Health
Organization,[3] the meridian system in acupuncture consists
of more
than 400 acupuncture points and 20 meridians
connecting some of
the
points. Most acupuncture points and
meridian points are the high
electric conductance points on
body surface and vice versa.[4, 5] A
model has been
proposed[6] that acupuncture points are organizing
centers
in
morphogenesis. At the macroscopic level, they are singular
points
(e.g. sinks, sources) in the morphogen gradient, phase
gradient
and
electromagnetic field. Meridians are
separatrices. The pattern of
magnetic field on the human
scalp mapped by SQUID (Superconducting
QUantum Interference
Device)[7] shows that the Governor Vessel is a
major
pathway
of magnetic flux on the scalp and also a separatrix which
divides
the scalp into two domains of different flow
directions.
Morphologically,
the Governor Vessel is also a
separatrix that divides
the body surface
into two symmetrical
parts. The acupuncture point GV20
is a singular
point - a
major sink at the surface magnetic field.[8]
This pattern is
consistent with the pattern of the meridian system,
but
different from
the distribution of any major nerve, lymphatic
or
blood vessel on the
scalp.
Intrinsic electric fields and currents are important factors in growth control, cell migration and morphogenesis:
A variety of cells including neurons, myoblasts and fibroblasts are sensitive to electric fields of physiological strength.[9] Somite fibroblasts translocate to the negative pole in a voltage gradient as small as 7 mV/mm.[10] Asymmetric calcium influx is crucial in the galvanotaxis which can be blocked or even reversed by various calcium channel blockers and ionophores.[11] In most cases, there is enhanced cell growth toward cathode and reduced cell growth toward anode in small continuous, pulsed or focal electric fields.[12,13] Some fast growing tissues, particularly tumors, are electrically negative in polarity. If a current from positive pole is applied over certain tumor, its growth can show significant retardation or even regression.[14] This is consistent with the fact that the fluorescent dye rhodamine 123, which has a delocalized positive charge, binds perferentially to some cancer cells and inhibits the cell growth.[15,16]
Flatworm Dugesia tigrina has an intrinsic dipole electric field with anterior negative and posterior positive. During regeneration, its anterior-posterior polarity can be reversed by an external electric field with an opposite polarity.[17] The dorsal-ventral polarity of chick epiblast can also be partially reversed by electric field of physiological strength.[18] Imposed electric field can cause polarization of mouse blastomeres.[19]
Change of electric activity correlates with signal transduction and can precede morphologic change.[20,21] For example, in axolotls and frogs, outward current can be detected at the site of future limb bud several days before the first cell growth.[22] This indicates that the electric conductance of the epithelium at the future limb bud - an organizing center, becomes higher before limb bud formation.
In development, the fate of a larger region is frequently controlled by a small group of cells. This small area is termed as an organizing center.[23] Organizing centers are likely to be the high electric conductance points on body surface: Epithelia appear to display their most active growth and morphogenesis in regions of high conductance.[12,22,9] This is supported by the finding of high density of gap junctions at the sites of organizing centers.[24,25,26] Epithelia usually maintain a 30-100 mV voltage difference across themselves with inside positive and outside negative.[27] Points of local high conductance on skin will also be extreme points of current density - sinks or sources of surface current. These singular points are important in growth control and are likely to be organizing centers. The importance of the electric field generated by epithelium in growth has been indicated in limb regeneration. After limb amputation, salamanders can regenerate their limbs - regenerators, while frogs can not - non-regenerators. The regenerators and non-regenerators have different electric field changes after amputation. By simulating the electric field of regenerators on the limb stumps of non-regenerators, partial regeneration can be induced. Simulating the electric field of non-regenerators on the limb stumps of regenerators can inhibit their regeneration. The optimal current density used in the simulation is within the range of physiological current density.[28,10]
Development involves bifurcation of the singular points. The first bifurcation in vertebrate development leads to two singular points: the animal pole and the vegetal pole. In immature oocytes of both frogs and fish, a transcellular current enters the animal pole and exits the vegetal pole. This current is present prior to the development of the pigment asymmetry. Several calcium channel blockers can rapidly reduce this current and cause maturation.[22] This result supports the notion that the change of electric field usually precedes the change in morphology and correlates with signal transduction. Some singular points are connected by separatrices which serve as major pathways of intrinsic electric currents and divide the body into domains of different electric current directions. Separatrices can be folds in extended sheets, boundaries between different structures or abrupt changes in the slope of a gradient .[6,29]
The distribution of organizing centers, acupuncture points and singular points in electric fields are closely related to the morphology of the organism. For example, the auricle, which has no major nerves or blood vessels but has the most complex surface morphology, also has the highest density of acupuncture points. According to the clockface model,[30,6] many organizing centers are at the extreme points of curvature on body surface, i.e. the locally most convex points (e.g. apical ectodermal ridge, head of hydra and other growth tips) or concave points (e.g. zone of polarizing activity). The same is true for acupuncture points. Most extreme points of the body surface curvature are acupuncture points, e.g. convex points: EX-UE11 Shixuan, EX-LE12 Qiduan, ST17 Ruzhong, ST42 Chongyang, ST45 Lidui, SP1 Yinbai, SP10 Xuihai, GV25 Suliao, EX-HN3 Yintang ... concave points: LI4 Hegu, CV17 Danzhong, KI1 Yongquan, SI19 Tinggong, TE21 Ermen, GB20 Fengchi, GB30 Huantiao, BL40 Weizhong, HT1 Jiquan, SI18 Quanliao, BL1 Jingming, CV8 Shenque ... Those acupuncture points which are not the extreme points of surface curvature may be vestigial organizing centers or more related to the growth control of internal structures.
Mechanism of meridian system based diagnosis
and
therapy
As mentioned above, the conductance of
organizing
centers varies with
morphogenesis. Similarly, the
conductance of
acupuncture points also
varies and correlates
with physiological
changes[5] and
pathogenesis.[31] The fact
that the change in electric
field precedes
morphologic
change[22] and manipulation of the electric
field can affect
the change[28] may shed light on medical
diagnosis[32] and
treatment of
many diseases. According to the model,[6]
the
network of organizing
centers retain their growth control
function
after morphogenesis, and
communicate with each other
(perhaps via gap
junctions,[33] nerves, etc.)
to maintain
proper forms and functions.
Therefore, an abnormality inside
the network may be detected by
measuring the electrical
parameters of
some points on its surface.
Malfunctions of
some organs can be preceded
by change of electric
parameters
from normal range and treated by
manipulation of the
interconnected singular points.
Singularity is a type of discontinuity, often indicates abrupt transition from one state to another. Small perturbations around singular points can have decisive effects on a system. As James Clerk Maxwell observed: Every existence above certain rank has its singular points ... At these points, influence whose physical magnitude is too small to be taken account of by a finite being, may produce results of the greatest importance.[34] As a technique of perturbation of singular points, acupuncture can be effective in treating various diseases[35] such as common cold, chronic obstructive pulmonary disease,[36] asthma,[37] myopia, diarrhea, constipation, diabetes, emesis,[38,39] enuresis,[40] postmenopausal syndrome,[41] obesity,[42] stroke,[43] hypertension[44] and cardiac arrest.[45]
An "annealing" mechanism may play a role in acupuncture and related techniques: Small perturbations at singular points elicit a "shock" to the system - activates and shakes the biological system out of its abnormal and unstable state. After activation, the system has a better chance to settle at a normal, more stable state. This may explain why there have been few negative side effects [46,47,42] of these techniques when properly administered, and the therapeutic effect can be achieved by a variety of stimuli[48] including electricity,[38] needling, temperature variation, laser,[49] and pressure. Similarly, organizing centers can also be activated by nonspecific stimuli.[23]
A principle in electroacupuncture therapy is that positive pulse stimulation of a point sedates its corresponding function while negative pulse stimulation tonifies the function.[50] This is analogous to the fact that cell growth is enhanced toward cathode and reduced toward anode in a pulsed electric field, in consistence with the model that the mechanism underlying acupuncture is similar to that of growth control.
Calcium
mediated signal
transduction in meridian system and
acupuncture?
Calcium ion concentration in meridians and acupuncture points
in
rabbit
was significant higher than that in non-meridian
and
non-acupuncture
points.[51] When calcium in the Quze
(PC3) acupuncture
point is chelated,
curative effect of
arrhythmia by puncturing Neiguan
(PC6) is blocked,
suggesting
that calcium is an important factor in
acupuncture and
probably involved in the activities of meridians.[52]
A more
informative experiment may be to use various calcium channel
blockers and compare their effects of local administration on
acupuncture, nerve conduction, blood and lymphatic
circulation. In both
excitable
cells and nonexcitable cells
of almost all the physiological
systems,
calcium as a second
messanger, intercellular messanger and
morphogen is
involved
in galvanotaxis, morphogenesis and various
physiological
functions.[21] Its electrochemical gradient contributes
to the
electric
potential across cell membrane. It can also affect
membrane potential by
mediating modification of ion channels
and
pumps.[53,54] Same calcium
waves can be elicited by
electrical,
mechanical or laser stimulation as
well as
chemical exposure, and
propagate through gap junctions.[55,56]
Similarly, the therapeutic
effects of acupuncture can be
achieved by a
variety of stimuli including
laser, mechanical
and electrical
stimulation.[48]
Beyond
nerves and blood vessels
Research on
acupuncture,
particularly the endorphin effect of acupuncture
analgesia
and its blockage by naloxone, clearly shows that some effect
of
acupuncture is mediated through nervous system.[57]
However, many
meridians do not correlate with major nerves
or blood vessels. The
distribution of the Governor Vessel on
the scalp and the auricular
acupuncture points[32,31,42] has
not been explained by
any model based
on nervous system
and/or circulatory system. The model
reviewed above
readily
explains these facts while accommodating the
findings of
acupuncture effect on nervous system and circulatory system.
The
meridian system is a distinct signal transduction system
which can be
measured by instrument such as SQUID. It
overlaps and interacts with
other systems but is not simply
part of nervous system or circulatory
system. Many
3nonexcitable2 cells have shown electrochemical
oscillation,
coupling, long range intercellular communication and can
participate in
the meridian signal transducation.[21]
In summary, the model has predicted and been supported by many research results in acupuncture, signal transduction and developmental biology. It can be further tested by mapping the electric field in vertebrate development with available techniques such as SQUID or vibrating probe.[22] The model predicts that organizing centers in vertebrates such as the dorsal lip of the blastopore, zone of polarizing activity and apical ectodermal ridge are major sinks or sources of surface current. These points bifurcate and give rise to some of the acupuncture points in adult. Current SQUID technology is adequate in detecting physiological electric current in embryo development generated by epithelium.[58] Available data showed that SQUID is sensitive enough to detect the individual difference in current pattern at GV20.[8] With the development of high Tc superconductors, the use of superconducting magnetic shield[59] and multi-channel SQUID[60,61] in the study of meridian system will yield further insight and circumvent the complications of the skin impedance measurement.
I thank Drs. Magnus Lou, San Wan, Andrew Marino, Frederick Kao, John Kao, Sarah Mei, K.S.Tsai, S.J.Chen, Richard Nuccitelli, Lionel Jaffe, Kenneth Klivington and others for their invaluable help and support.
Box 275
80 E. Concord Street
Boston,
MA
02118
Telephone: 617-825-5812
Email: cshang@acs.bu.edu
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