How do acupuncture and moxibustion act? - Focusing on the progress in Japanese acupuncture research -.

The mechanisms of action of acupuncture and moxibustion as reported by Japanese researchers are reviewed. The endogenous opioid-mediated mechanisms of electroacupuncture (EA) as used in China are well understood, but these are only one component of all mechanisms of acupuncture. These studies emphasize the similarity of the analgesic action of EA to various sensory inputs to the pain inhibition mechanisms. In Japanese acupuncture therapy, careful detection of the acupuncture points and fine needling technique with comfortable subjective sensation are considered important. The role of polymodal receptors (PMR) has been stressed based on the facts that PMRs are responsive to both acupuncture and moxibustion stimuli, thermal sensitivity is essential in moxibustion therapy, and the characteristics of acupuncture points and trigger points are similar to those of sensitized PMRs. Acupuncture and moxibustion are also known to affect neurons in the brain reward systems and blood flow in skin, muscle, and nerve. Axon reflexes mediated by PMRs might be a possible mechanism for the immediate action of acupuncture and moxibustion. Reports on the curative effects of acupuncture on various digestive and urological disorders are also reviewed briefly.

Acupuncture stimulates the release of serotonin, but not dopamine, in the rat nucleus accumbens.

Acupuncture has been introduced as one of the available therapies widely used in alternative medicine, but it has not achieved widespread acceptance with scientific evidence. Furthermore there are still many unanswered questions about the basic mechanisms of acupuncture. To investigate the neuropharmacological mechanisms of oriental acupuncture, we studied the acupuncture-induced changes of in vivo monoamine release in the rat brain. A microdialysis guide cannula was implanted into the nucleus accumbens (ACC), which plays an important role in the brain reward system. Acupuncture treatment at the unilateral or bilateral Shenshu (bladder urinary channel 23) acupoints, located on the both sides of the spinous processes on the lower back, was carried out for 60 min in freely moving rats, and the dopamine (DA) and serotonin (5-HT) contents of the microdialysates in the ACC were measured simultaneously. In rats subjected to acupuncture at bilateral Shenshu acupoints, increases of 5-HT release in the ACC were observed at 20 min of acupuncture treatment and continued until 40 min after acupuncture was ended. Acupuncture at a unilateral Shenshu acupoint increased the release of 5-HT at 20 min compared with that in the sham-control group. Five-HT release returned to the baseline level at 120 min. The effects of acupuncture at bilateral Shenshu acupoints on the release of 5-HT in the ACC were greater than that of unilateral acupuncture treatment. In contrast, DA release in the ACC was not changed following acupuncture treatment. Effective acupuncture increased and prolonged the activity of serotonergic neurons in the reward system pathway of the brain. This suggests that oriental acupuncture therapy may be effective for the treatment of emotional disorders, drug abuse and alcoholism.

Effect of moxibustion on dopaminergic and serotonergic systems of rat nucleus accumbens.

Acupuncture and moxibustion are traditional medical treatments that have come to play important roles in complementary and alternative medicines. Moxibustion also has a long history as a folk remedy in Japan, particularly due to the technical simplicity and selective efficacy on certain types of disease and distress. This study examined the effects of moxibustion focusing on the brain reward system, particularly in the nucleus accumbens. The effects of moxibustion stimulation at various sites and frequencies on monoamine levels of adult male Sprague-Dawley rats were examined using high-preformance liquid chromatography of dissected nucleus accumbens tissues. The rats weighing 290-310 g were divided into 3 groups according to the moxibustion point used: hindlimb, lumbar or parietal points. Each group was further divided into 3 subgroups, with stimulation for 10 consecutive days, for 1 day, or sham treatment (control). On each day of stimulation, 5 moxibustion cones with a peak temperature of 200 degrees C were applied consecutively. Stimulation of any point on 1 day only did not change dopamine or serotonin levels, but lumbar stimulation significantly increased the metabolic turnover of dopamine. Conversely, stimulation for 10 consecutive days resulted in significantly decreased serotonin levels for hindlimb and parietal stimulations, and significantly increased 5-hydroxyindolacetic acid/serotonin ratio for hindlimb stimulation. These results suggest that the metabolic turnover of serotonin release may be accentuated by moxibustion in a reward-related brain area. Moxibustion over consecutive days, especially that to peripheral regions, appears most efficient to influence on monoamine levels in the nucleus accumbens.

Alterations in the function of cerebral dopaminergic and serotonergic systems following electroacupuncture and moxibustion applications: possible correlates with their antistress and psychosomatic actions.

Alterations in cerebral monoamines following application of electroacupuncture were investigated using conscious rats with and without application of restraining stress. The dopamine and serotonin levels were significantly decreased in the nucleus accumbens, caudate putamen, and lateral hypothalamus and increased in the dorsal raphe nucleus by restraining stress. On the other hand, application of electroacupuncture on the lumbar and hindlimb segments eliminated the above changes in dopamine, while the changes in serotonin were attenuated by lumbar and hindlimb electroacupuncture. However, the effects of hindlimb electroacupuncture were greater than those of lumbar electroacupuncture. These results clearly indicate that lumbar and hindlimb electroacupuncture stimulations have differential effects on brain monoaminergic neurons in rats exposed to restraining stress. Moxa burning stimulation was applied to the lumbar and hindlimb segments of rats without restraining stress. The dopamine level was significantly increased in the midbrain substantia nigra-ventrotegmental area by hindlimb moxibusion. On the other hand, the serotonin levels were significantly increased in the nucleus amygdala by lumber moxibusion and decreased in the nucleus accumbens by hindlimb moxibusion. The present results indicate that electroacupuncture applied to the lumbar and hindlimb segments has an antistress effect, while the application of moxibustion to the lumbar and hindlimb segments was likely to stimulate the functions of mesocortical and mesolimbic dopaminergic and serotonergic neurons. We suggest that functional alterations in cerebral dopaminergic and serotonergic neurons are involved in the clinical efficacy of electroacupuncture and moxibustion, especially because of their antistress and psychosomatic actions.