sábado, 1 de dezembro de 2007

Biological Mechanisms of Acupuncture

The recent advances of the knowledge on Neurophysiology and Neuroscience, allowed defining Acupuncture as a method which aims to induce neuromodulation by peripheral neural stimulation, in order to promote changes in the sensory, motor, autonomic, visceral, hormonal, immune and brain functions, with therapeutic outcomes. The biological mechanisms of Acupuncture are understood following the consolidation of the neural stimulation paradigm[1], [2].

Medical Acupuncture, the result of a historical evolution[3], has its foundations lays on the evidences of clinical efficacy[4], as well as on the knowledge of the biological mechanisms of action[5], [6], synthetically defined as neuromodulation[7].

It has been stated[8] that even being apparently similar to the Chinese traditional practice, modern Acupuncture is actually very different. The ancient theoretical explanations for disease and therapeutics, based in peculiar conceptions like the flowing of a supposed ethereal substance named Qi (Chee) are replaced by neurobiological ones, like the mechanisms of the Acupuncture analgesia, which are conceived as resultant of the stimulation and modulation of the activity of nerve fibers.

The knowledge on the biological bases of Acupuncture[9] achieved such a degree of deepness that created the need of making an update of its theoretical bases, and a subsequent renew on the method’s practice[10]. Data provided by the basic[11] and the clinical[12] research expand and does not reduce the method, in addition to found in a solid ground the practice of Medical Acupuncture, opening new therapeutic purposes of the method.

The therapeutic process of Acupuncture, that begin with the stimulation of sites that provide access to the peripheral neural net, promotes analgesia, motor rehabilitation, normalization of the control and regulation of organic functions, modulation of immunity, of endocrine autonomic and mental functions, and activation of the regenerative processes[13].

Acupuncture, as a group of methods for peripheral neural stimulation, exerts an effect of physiologic re-learning[14], [15], in two ways – modifying neuronal connectivity patterns, by means of the activation of peripheral devices of informational input that operate as commands in an interface with decision centers, and by triggering long term potentiation (LTP), as a consequence of the modulation of neurotransmitters required to the effectiveness of changes in memory processes.

It has also been reported that the repeated stimulation of the physiologic pain inhibitory systems and autonomic regulation train the organism to continue with this activity, keeping for long term the effects like pain relief, in a way similar to the disturbed autonomic functions training[16].

On the other hand, the recent advances in pathophysiology and on the knowledge of the mechanisms of many clinical conditions, like the dysfunctional syndromes and the chronic conditions, for which there is a growing interest, qualify Medical Acupuncture as one of the first-choice methods, for the treatment of this kind diseases[17].

[1] MAYER D.J., Biological mechanisms of acupuncture. Prog Brain Res, 122: 457-77, 2000

[2] ANDERSON S., LUNDEBERG T., Department of Physiology, University of Gotenborg, Sweden Acupuncture – from empiricism to science: functional knowledge of acupuncture effects in pain and disease. Med Hypotheses 45(3), 271-81, Sep 1995

[3] ULETT G.A., HAN J.S., HAN A.P., Traditional and Evidence-Based Acupuncture: History, Mechanisms, and Present Status. South Med J 91(12):1115-1120, 1998

[4] FILSHIE J., CUMMINGS M., Acupuntura médica ocidental. in ERNST E., WHITE A.: Acupuntura: uma avaliação científica. Ed. Manole, São Paulo, 2001

[5] KLEINHENZ J., Acupuncture mechanisms, indications and effectiveness according to recent western literature. Am Jour Acup 23(3): 211-18, 1995

[6] POMERANZ B., STUX G., Scientific Bases of Acupuncture. Springer Verlag, Berlin, p. 94-9, 1989

[7] VELASCO F., Neuromodulation: an overview. Arch Med Res 31(3): 232-6 May-Jun 2000

[8] BERMAN B.M., SWYERS J.P., EZZO J., What is Acupuncture? The Evidence for Acupuncture as a Treatment for Rheumatologic Conditions. Rheumatic Diseases Clinics of North America 26(1), Feb 2000

[9] PLUMMER J.P., Acupuncture points and cutaneous nerves. Experientia, Nov 15, 35:11, 1534-5, 1979

[10] MELZACK R., WALL P.D., Textbook of Pain. 3 ed, Churchill Livingstone, UK, 1994

[11] LEVY B., MATSUMOTO T., Pathophysiology of acupuncture: nervous system transmission. Am Surg, 1975 Jun, 41:6, 378-84

[12] ERNST E., Clinical effectiveness of acupuncture: An overview of systemic reviews in Acupuncture - A Scientific Appraisal. E, Ernst and A, White, Oxford, Ed, Butterworth- Heinemann, p 107-127, 1999

[13] KAZUSHI N., HIDETOSHI ., KEISHI Y., KAZUHIRO Y., Decreased heart rate by acupuncture stimulation in humans via facilitation of cardiac vagal activity and suppression of cardiac sympathetic nerve. Neuroscience Letters 227:3:165-168, 1997

[14] BENSOUSSAN A., Does Acupuncture therapy resemble a process of physiological learning? Am J Acupun 22(2):137-44, 1994

[15] LEE T.N., Academy of Pain Research, San Francisco, CA, Thalamic Neuron Theory: theoretical basis for the role played by the central nervous system (CNS) in the causes and cures of all diseases. Med-Hypotheses, 43(5): 285-302, Nov 1994

[16] KLIDE A.M., An hypothesis for the prolonged effect of Acupuncture. Acupun & Eletro-Therap Res Intl Journal 14:141-7, 1989

[17] GOLDSTEIN J.A., Betrayal by the Brain: the neurologic basis of chronic fatigue syndrome, and neural network disorders. The Haworth Medical Press, NY/USA, 1996

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