Convergence from the preoptic area and arcuate nucleus to the median eminence in acupuncture and nonacupuncture point stimulation analgesia

Role of acupuncture in the treatment of migraine

Since the last Cochrane review of acupuncture and headache in 2001, which found methodological and/or reporting shortcomings in the majority of the studies, several large, randomized trials on the effectiveness of acupuncture as a treatment for headache have been published. Following a brief overview of the pathophysiology of migraine and possible action mechanisms of acupuncture, we look at current studies on acupuncture and migraine and discuss the results. From these results and our own studies on acupuncture and migraine, we conclude that a 6-week course of acupuncture is not inferior to a 6-month prophylactic drug treatment, but that specific Chinese point selection, point stimulation and needling depth are not as important as had been thought. The review suggests that acupuncture should be integrated into existing migraine therapy protocols.

Analgesic action of acupuncture and moxibustion: a review of unique approaches in Japan

The mechanism of acupuncture analgesia (AA) is one of the most widely researched topics in complementary and alternative medicine (CAM) based on modern medical methodology. Endogenous opioid-mediated mechanisms of acupuncture have been well established since the 1970s. In this review, we have covered the progress of AA research by Japanese investigators. In particular, we have reviewed the physiological basis of analgesic effects induced by acupuncture and moxibustion, including the actions of endogenous opioid and diffuse noxious inhibitory controls (DNICs), and the afferent fibers participating in acupuncture and moxibustion stimuli are discussed.

Modulation of natural killer cell activity affected by electroacupuncture through lateral hypothalamic area in rats

Electroacupuncture (EA) has been reported to modulate natural killer cell (NK cell) activities. Also it is well known that hypothalamus directly mediates the effects of EA on analgesia. Especially lateral hypothalamic area (LHA) is related to splenic NK cell activities. In order to investigate the relationship between hypothalamus and effects of EA on NK cell activity, lesions have been made bilaterally at LHA of Spraque-Dawley rats. Subsequently, NK cell cytotoxities of normal and lesioned rats were measured with (51)Cr release immunoassay after EA stimulation for 2 and 14 days. NK cell activity of EA group was significantly higher than sham group. In addition, lesions abolished effects of EA on NK cell activity. These results strongly suggest that LHA is closely related to increase of NK cell activity induced by EA.

Inhibitory effects of electroacupuncture on stress responses evoked by tooth-pulp stimulation in rats

The mechanism of electroacupuncture (EA) on the stress responses induced by tooth-pulp stimulation was investigated in anesthetized adult female Sprague-Dawley rats. The Hoku point in the Chinese meridian was used for acupuncture stimulation. Constant rectangular current (1 mA) pulses of 5-ms duration were delivered at 3 Hz through a pair of needles for 15 min. As for stress response indexes, we have monitored changes in arterial blood pressure and the levels of blood catecholamines, corticosterone, and ACTH. Arterial blood pressure was increased by high frequency stimulation (0.1 mA, 0.5 ms, 100 Hz for 15 s) of tooth-pulp in the control condition. After EA, we did not observe the same responses of the arterial blood pressure changes with the same stimuli. The tooth-pulp stimulation increased the concentrations of plasma norepinephrine (NE), epinephrine (E), dopamine (DA), corticosterone, and ACTH significantly from the levels of those before stress. After treatment with EA, the stress-induced increase in NE, DA, corticosterone, and ACTH but not the rise in E, were inhibited. When naloxone, an opioid antagonist, was administered intraperitoneally before EA, the effects of EA on stress responses were reduced. In this study, it can be suggested that EA has not only an analgesic effect but also suppressive effects on the stress responses primarily through the mediation of an endogenous opioid.

The acupuncture point and its connecting central pathway for producing acupuncture analgesia

Characteristics of the acupuncture point in producing acupuncture analgesia (AA) were examined by the inhibition of noxious responses in the brain stem reticular formation, potentials, and neuronal activity in the dorsal periaqueductal central gray (D-PAG), and analgesia caused by low frequency stimulation of the acupuncture point. As a result, stimulation of the muscle beneath the acupuncture point was found to be effective in producing AA. AA measured by tail flick, vocalization, and writhing tests was abolished by hypophysectomy, and by antiserum of beta-endorphin administered into the 3rd ventricle. The pathway from the D-PAG to the anterior hypothalamus (AA-AH) in the AA afferent pathway from the acupuncture point to the pituitary gland was determined. The lateral hypothalamus, lateral septum, cingulate bundle, dorsal-hippocampus, and habenulo-interpeduncular tract were found, in addition to regions previously found, to belong to the AA afferent pathway. A network of divergence and convergence in their rostral and caudal relations was observed. The AA afferent pathway diverges from the D-PAG, converges to the HP, and then projects to the AA-AH.

Descending pain inhibitory system involved in acupuncture analgesia

The descending pain inhibitory system (DPIS) associated with acupuncture analgesia (AA), caused by low frequency stimulation of an acupuncture point, was identified by the results of lesion and stimulation procedures previously determined to differentiate the afferent and efferent paths in rats. The DPIS starts in the posterior arcuate nucleus and descends to the hypothalamic ventromedian nucleus (HVM) from whence it divides into two pathways: one path, the serotonin mediated path, descends through the ventral periaqueductal central gray (V-PAG) and then to the raphe magnus (RM). The other, the noradrenaline mediated path, descends through the reticuloparagigantocellular nucleus (NRPG) and part of the reticulogigantocellular nucleus (NRGC). The afferent and efferent paths are both present in the RM and NRGC, and were separately identified by means of the analgesia (SPA) produced by stimulation of the separate regions in AA responders and nonresponders, because SPA of these regions in nonresponders produced only efferent pathway mediated analgesia.

Positive feedback action of pituitary beta-endorphin on acupuncture analgesia afferent pathway

Potentials in the final sector of the afferent pathway from the acupuncture point (AP) were enhanced by intraperitoneal 0.5 mg/kg morphine without changing the threshold of AP stimulation and greatly decreased by hypophysectomy. The decreased potentials were restored to the control level by morphine (0.5 mg/kg, IP). Potentials evoked in the final sector of the afferent pathway from the nonacupuncture point (NAP) by NAP stimulation after lesion of the analgesia inhibitory system were greatly enhanced by corticotropin (ACTH) (0.25 mg/kg, IP) and greatly decreased by hypophysectomy. Diminished potentials were restored to the control level by ACTH (0.25 mg/kg, IP). Both morphine (0.5 mg/kg, IP) and ACTH (0.25 mg/kg, IP) produced analgesia, but morphine did not affect acupuncture analgesia (AA) and ACTH did not affect nonacupuncture point stimulation-produced analgesia (NAA). All analgesia, that due to 0.5 mg/kg morphine or 0.25 mg/kg ACTH, AA, and NAA were abolished by hypophysectomy. The abolished AA and NAA were restored by 0.5 mg/kg morphine and 0.25 mg/kg ACTH, respectively. Hence, beta-E and ACTH liberated from the pituitary gland by stimulation of an AP and NAP may act as positive feedback on the AA and NAA afferent pathways, respectively.

Analgesia inhibitory system involvement in nonacupuncture point-stimulation-produced analgesia

Acupuncture analgesia (AA), caused by low-frequency stimulation of an acupuncture point (AP)--in this case the tibial muscle--was augmented. Nonacupuncture analgesia (NAA), caused under certain circumstances by stimulation of a nonacupuncture point (NAP)--in this case the abdominal muscle--was unmasked by lesion in the lateral centromedian nucleus of the thalamus (L-CM) or part of the posterior hypothalamus (I-PH). Stimulation in these regions suppressed the augmented part of the AA and blocked the NAA. These regions were, collectively, given the name analgesia inhibitory system. NAA was abolished, the same as AA, by hypophysectomy. The pathways from the AP and NAP to the pituitary gland were different. AA was naloxone reversible, and NAA was dexamethasone reversible. The analgesia inhibitory system is activated nonspecifically by stimulation of either an AP or NAP. It ascends to the I-PH, thence to the L-CM, and ultimately inhibits the pathway nonspecifically connected to the NAP and AP in the lateral part of the periaqueductal central gray (PAG), without affecting the pathway specifically connected to the AP. Thus, only stimulation of an AP will produce analgesia, whereas stimulation of an NAP will not normally produce analgesia. Stress-induced analgesia (SIA) is produced in a different way than AA or NAA.