• “Acupuncture may activate the hypothalamus and the pituitary gland, resulting in a broad spectrum of systemic effects.
• “Alteration in the secretion of neurotransmitters and neurohormones and changes in the regulation of blood flow, both centrally and peripherally, have been documented.
• “There is also evidence of alterations in immune functions produced by acupuncture. Which of these and other physiological changes mediate clinical effects is at present unclear.
• “Findings from basic research have begun to elucidate the mechanisms of action of acupuncture, including the release of opioids and other peptides in the central nervous system and the periphery and changes in neuroendocrine function. Although much needs to be accomplished, the emergence of plausible mechanisms for the therapeutic effects of acupuncture is encouraging.”

    One of the studies cited by the NIH was conducted by Abass Alavi, M.D., chief of nuclear medicine at the University of Pennsylvania Medical Center, who showed that acupuncture affects the flow of blood in the brain. He used SPECT (single photon emission computed tomography) to view the brains of four people with pain and five pain-free people who served as the control group. Dr. Alavi found that after acupuncture needles were inserted, all of the patients had increased blood flow to the thalamus, the area of the brain that relays pain and other sensory messages. Because the brains of the pain-free group showed the same reactions as those with pain, the changes in blood flow could not be attributed to placebo.

1. PET-Scans of the brain during acupuncture (Dold, 1998): University of California Irvine professor and physicist Zang-Hee Cho, a member of the highly respected National Academy of Science, the inventor of an early version of the Positron Emission Tomograph, or PET scan, and a pioneer of the MRI scanner, both of which have revolutionized our ability to see into the body and brain, found that stimulation of the vision-related acupoint showed the same reaction in the brain as stimulation of the eye. As the acupuncture signal passes to the brain via nerves, it possibly stimulates the hypothalamus, the “executive center” of the brain, responsible for the production and release of hundreds of neurochemicals, Cho said.
   
2. Acupuncture: pain management coupled to immune stimulation (Gollub, 1999): “The phenomenon of acupuncture is both complex and dynamic. Recent information demonstrates that acupuncture may exert its actions on pain and immune processes. The coupling of these two systems occurs via common signaling molecules, i.e., opioid peptides. In this regard, we surmise that:
   
• Opioid activation leads to the processing of opioid peptides from their precursor, proenkephalin, and the simultaneous release of antibacterial peptides contained within the precursor as well. Thus, central nervous system pain circuits may be coupled to immune enhancement.
• Furthermore, acupuncture needle manipulation elicited signal increases bilaterally in the region of the primary and secondary somatosensory corticies in human brain as determined by magnetic resonance imaging.
• The maps reveal marked signal decreases bilaterally in multiple limbic and deep gray structures including the nucleus accumbens, amygdala, hypothalamus, hippocampus, and ventral tegmental area.
• Taken together, we surmise a major central nervous system pathway as well as local pain and immune modulation during acupuncture.”
  
3. (Fu, 2000): “In recent years, more and more laboratory proof has accumulated that acupuncture can
   
   • change the charge and potential of neurons,
   
   
   • the concentrations of K(+), Na(+), Ca(++) and
   
   
   • the content of neuro-transmitters such as aspartate, and taurine and
   
   
   • the quantities of neuro-peptides such as beta-endorphin and leu-enkephalin.
   
   
   • All these phenomena are directly related to nerve cells.”
     
4. Immune System effects of Acupuncture (Joos, 2002): “The following changes were found in the TCM group: within the lymphocyte subpopulations the CD3+ cells (p = 0.005) and CD4+ cells (p = 0.014) increased significantly. There were also significant changes in cytokine concentrations: interleukin (IL)-6 (p = 0.026) and IL-10 (p = 0.001) decreased whereas IL-8 (p= 0.050) rose significantly. Additionally, the in vitro lymphocyte proliferation rate increased significantly (p = 0.035) while the number of eosinophils decreased from 4.4% to 3.3% after acupuncture (p > 0.05). The control group, however, showed no significant changes apart from an increase in the CD4+ cells (p = 0.012).”
   
5. Difference between Manual and Electro Acupuncture (Kong, 2002): “Results showed that electroacupuncture mainly produced fMRI signal increases in precentral gyrus, postcentral gyrus/inferior parietal lobule, and putamen/insula; in contrast, manual needle manipulation produced prominent decreases of fMRI signals in posterior cingulate, superior temporal gyrus, putamen/insula. These results indicate that different brain networks are involved during manual and electroacupuncture stimulation. It suggests that different brain mechanisms may be recruited during manual and electroacupuncture.”