[Problems of acupoint injection therapy].

There are a large number of clinical reports that acupoint injection therapy is effective, but there are still some basic problems that have not been effectively resolved, such as the type, dosage, concentration and compatibility of acupoint injection drugs. This article analyzes and discusses the problems of acupoint injection therapy in five aspects: the effect of acupoint injection on local tissues, the study of mechanism, the best treatment plan and advantages, and the similarities and differences with local injection therapy.

[Myofascial trigger point: an indicator of acupoint sensitization].

OBJECTIVE: The present study is to investigate the characteristic distribution of primary pain points and referred pain areas in patients with knee-joint pain diseases, therefore revealing the correlation between the myofascial trigger point and acupoint sensitization. METHODS: A total of 483 patients (320 men and 163 women, 36 to 72 years in age) with knee-joint pain recruited from 4 clinical centers were observed from July, 2017 to April, 2019 in the present study. The areas of primary and referred pain in these patients were detected by thumb-pressing and marked on human anatomic atlas. RESULTS: Of the 483 enrolled participants, 336 had lesion sites or tender points around the injured knee joint, and 147 with myofascial pain syndrome showed referred pain spots (zones) in the knee joint area. In 105 patients with patellar tendonitis, epiphysitis of the tibial tubero-sity, or quadriceps tendonitis, the pain area was mainly distributed in the anterior region of the knee. In 76 patients with medial collateral ligament injury, medial meniscal lesion, goose foot bursitis or semimembranosus ending-point inflammation, the pain points mainly occurred in the medial area of the knee. In 127 patients with lateral collateral ligament, lateral meniscus lesion, iliotibial band tendonitis, popliteus or triceps tendinitis, the pain spots were found in the lateral region of the knee. In 28 patients with posterior cruciate ligament injury or popliteal fossa tendonitis, the local pain was found to be at the back of the knee. Referred pain areas were normally detected in the lateral femoral muscles (43 cases), anterior femoral muscles (39 cases), adductor group of femur (26 cases), posterior popliteal fossa muscles group (15 cases), hamstrings (13 cases) and medial leg (11 cases)．. CONCLUSION: The primary pain areas or spots of the knee injury mainly distribute around the joint, whereas those of each muscle group lesion are often located in their respective skeletal muscle. Most of the referred pain areas often occur in the distal end of skeletal muscle and around the knee joint. Primary myofascial trigger points may be considered to be an indicator of acupoint sensitization.

[Colorectal nociceptive signal input facilitates impact of acupoint stimulation of "Zusanli" (ST 36) on electrical activities of wide dynamic range neurons in lumbar spinal cord in rats].

OBJECTIVE: To observe changes of electrical activities of wide dynamic neurons (WDR) in the lumbar spinal cord after electroacupuncture (EA) stimulation of "Zusanli" (ST 36) during colorectal distension in rats, so as to analyze alternations of acupoint's functions under pathological conditions. METHODS: Experiments were performed in male Sprague-Dawley rats. Visceral nociceptive information input was generated by colorectal distension (CRD). Extracellular discharges of WDR neu- rons in the dorsal horns of L(1-3) spinal cord were recorded using glass micropipettes and a microelectrode amplifier. EA stimulation (15 Hz, 1, 4, 7, 10 mA) was applied to ipsilateral "Zusanli" (ST 36) area. RESULTS: A total of 40 neurons were recorded in the present study. Under no CRD conditions, the firing rates of WDR neurons were significantly increased by (18.12 +/- 13.56)% (1 mA), (152.38 +/- 36.19)% (4 mA), (231.21 +/- 49.74)% (7 mA) and (331.54 +/- 61.89)% (10 mA) respectively after EA sti- mulation of ST 36. Under CRD conditions, the firing rates of these WDR neurons were increased by (226.78 +/- 39.59)% (1 mA), (282.80 +/- 47.54)% (4 mA), (343.06 +/- 58.35)% (7 mA), and (338.62 +/- 80.04)% (10 mA) respectively after EA stimulation. It showed a considerablely increased sensitivity of electrical activities of WDR neurons to EA stimulation during CRD nociceptive stimulation. CONCLUSION: colorectal distension (visceral nociceptive stimulation) can strengthen the sensitivity of acupoint-EA stimulation-induced increase of firing rates of WDR neurons in the dorsal horns of the lumbar spinal cord in rats, suggesting a potentiation of the acupoint action under visceral nociceptive signal inputs.

Changes in responses of neurons in spinal and medullary subnucleus reticularis dorsalis to acupoint stimulation in rats with visceral hyperalgesia.

The purpose of this study was to explore the mechanism of acupoints sensitization phenomenon at the spinal and medulla levels. Experiments were performed on adult male Sprague-Dawley rats and visceral noxious stimuli was generated by colorectal distension (CRD). The activities of wide dynamic range (WDR) and subnucleus reticularis dorsalis (SRD) neurons were recorded. The changes of the reactions of WDR and SRD neurons to electroacupuncture (EA) on acupoints of "Zusanli-Shangjuxu" before and after CRD stimulation were observed. The results showed that visceral nociception could facilitate the response of neurons to acupoints stimulation. In spinal dorsal horn, EA-induced activation of WDR neurons further increased to 106.84 ± 17.33% (1.5 mA) (P < 0.001) and 42.27 ± 13.10% (6 mA) (P < 0.01) compared to the neuronal responses before CRD. In medulla oblongata, EA-induced activation of SRD neurons further increased to 63.28 ± 15.96% (1.5 mA) (P < 0.001) and 25.02 ± 7.47% (6 mA) (P < 0.01) compared to that before CRD. Taken together, these data suggest that the viscerosomatic convergence-facilitation effect of WDR and SRD neurons may underlie the mechanism of acupoints sensitization. But the sensitizing effect of visceral nociception on WDR neurons is stronger than that on SRD neurons.

Neurons in the nucleus tractus solitarius mediate the acupuncture analgesia in visceral pain rats.

The study investigated the role of nucleus tractus solitarius (NTS) neurons in electroacupuncture (EA) analgesia in colorectal distension (CRD) rats. NTS neurons responding to both CRD test and EA conditioning stimulations were considered somato-visceral convergent neurons. The neuronal activities evoked by graded CRD showed multiple firing patterns indicating multisynaptic connections. Some of the CRD excitatory neurons were inhibited by EA and vice versa. There was no discrepancy among different acupoints in inducing the changes of unit discharges. Conclusively, EA could regulate CRD related neurons in the NTS through polysynaptic cross-talk mechanism, which mediates EA analgesia on visceral pain in anesthetized rats.

[Effects of acupuncture at "Tianshu" (ST 25) on electro-activity and mechanical motility of migrating motor complex during jejunal digestion period in rats with detached jejunum].

OBJECTIVE: To observe the effects of acupuncture at "Tianshu" (ST 25) on electro-activity and mechanical motility at different phases of migrating motor complex (MMC) during jejunal digestion period in rats with detached jejunum, so as to explore the effect and mechanism of acupuncture on regulating intestinal movement. METHODS: Sixteen adult SD rats were selected. Electrodes were implanted in the serous membrane of intestinal smooth muscl.e and high-sensitivity sensors of strain gauge were sutured on serosal surface, and then the rat was anesthetized and its jejunum was detached. Electro-acriviry and mechanical motility of jejunal smooth muscle were recorded simultaneously. Acupuncture was applied at "Tianshu" (ST 25) at MMC I , MMCII and MMC III, respectively, to observe its influence on electro-activity and mechanical motility. RESULTS: At phase of MMC I, there was no obvious change of the fast wave before and after the acupuncture, while the frequency and amplitude of slow wave and mechanical motility were both significantly decreased compared with baseline (P < 0.01). At MMCII-Ill, the frequency and amplitude of fast wave, slow wave and motility were all significantly decreased compared with baseline (P < 0.01). Acupuncture at "Tianshu" (ST 25) had prohibited effects on electro-activity and mechanical motility of jejunal smooth muscle in rats with detached jejunum. CONCLUSION: Acupuncture at "Tianshu" (ST 25) has obvious prohibited effects on electro-acrivity and mechanical motility at MMC I , MMC II and MMC III time phases in rats with detached jejunum. The possible mechanism is that acupuncture at "Tianshu" (ST 25) could prohibit jejunum movement through reflex path of skin-sympathetic.

[Effects of acupuncture at "Tianshu" (ST 25) on electrical and mechanical motor of jejunum smooth muscles at different phases of the interdigestive migrating motor complex in normal rats].

OBJECTIVE: To observe the effect of acupuncture stimulation of "Tianshu" (ST 25) on electrical and mechanical activities of jejunum smooth muscle at different phases of interdigestive migrating motor complex (MMC) in normal rats, so as to explore its mechanism underlying regulation of intestinal function. METHODS: A total of 16 adult SD rats were used in the present study. After 18-24 hours' fasting (with free access to water), the rats were subjected into experimental observation. Electromyogram and intestinal mechanical motor were respectively recorded by using implanted metal electrodes and strain gauge (sutured to the serosal surface of the jejunum) and biophysiological amplifier system. Manual acupuncture stimulation was applied to ST 25 for about 1 min at phase I, II and III of MMC, respectively. RESULTS: Following manual acupuncture stimulation of ST 25, the mean frequencies and amplitudes of both fast and slow waves of electrical activities and muscular contraction tension of the jejunum smooth muscle at phase II and III of MMC were significantly decreased compared to their baseline levels (P < 0.01). No significant changes were found in the mean frequency and amplitude of fast wave of electrical activities of the jejunum smooth muscle at phase I of MMC after acupuncture stimulation of ST 25 (P > 0.05). CONCLUSION: Acupuncture stimulation of ST 25 can inhibit the jejunum electrical and mechanical activities at phase II and III of MMC in normal rats, probably via somato-sympathetic reflex.

Acupuncture at heterotopic acupoints enhances jejunal motility in constipated and diarrheic rats.

AIM: To investigate the effect and mechanism of acupuncture at heterotopic acupoints on jejunal motility, particularly in pathological conditions. METHODS: Jejunal motility was assessed using a manometric balloon placed in the jejunum approximately 18-20 cm downstream from the pylorus and filled with approximately 0.1 mL warm water in anesthetized normal rats or rats with diarrhea or constipation. The heterotopic acupoints including LI11 (Quchi), ST37 (Shangjuxu), BL25 (Dachangshu), and the homotopic acupoint ST25 (Tianshu), and were stimulated for 60 s by rotating acupuncture needles right and left at a frequency of 2 Hz. To determine the type of afferent fibers mediating the regulation of jejunal motility by manual acupuncture, the ipsilateral sciatic A or C fibers of ST37 were inactivated by local application of the A-fiber selective demyelination agent cobra venom or the C fiber blocker capsaicin. Methoctramine, a selective M2 receptor antagonist, was injected intravenously to identify a specific role for M2 receptors in mediating the effect of acupuncture on jejunal motility. RESULTS: Acupuncture at heterotopic acupoints, such as LI11 and ST37, increased jejunal motility not only in normal rats, but also in rats with constipation or diarrhea. In normal rats, manual acupuncture at LI11 or ST37 enhanced jejunal pressure from 7.34 ± 0.19 cmH2O to 7.93 ± 0.20 cmH2O, an increase of 9.05% ± 0.82% (P < 0.05), and from 6.95 ± 0.14 cmH2O to 8.97 ± 0.22 cmH2O, a significant increase of 27.44% ± 1.96% (P < 0.01), respectively. In constipated rats, manual acupuncture at LI11 or ST37 increased intrajejunal pressure from 8.17 ± 0.31 cmH2O to 9.86 ± 0.36 cmH2O, an increase of 20.69% ± 2.10% (P < 0.05), and from 8.82 ± 0.28 cmH2O to 10.83 ± 0.28 cmH2O, an increase of 22.81% ± 1.46% (P < 0.05), respectively. In rats with diarrhea, MA at LI11 or ST37 increased intrajejunal pressure from 11.95 ± 0.35 cmH2O to 13.96 ± 0.39 cmH2O, an increase of 16.82% ± 2.35% (P < 0.05), and tended to increase intrajejunal pressure (from 12.42 ± 0.38 cmH2O to 13.05 ± 0.38 cmH2O, an increase of 5.07% ± 1.08%, P > 0.05), respectively. In contrast, acupuncture ST25, a homotopic acupoint, decreased not only intrajejunal pressure, but also significantly decreased frequency in normal rats and rats with constipation or diarrhea. Following demyelination of Aδ fibers, acupuncture at ST37 again augmented intrajejunal pressure to 121.48% ± 3.06% of baseline. Following capsaicin application for 24 h, acupuncture at ipsilateral ST37 increased intrajejunal pressure significantly to 106.63% ± 1.26% of basal levels when compared to measurements prior to capsaicin treatment (P < 0.05). Acupuncture at LI11, ST37, or BL25 significantly rescued methoctramine-mediated inhibition of jejunal motility amplitude from 42.83% ± 1.65% to 53.43% ± 1.95% of baseline (P < 0.05), from 45.15% ± 2.22% to 70.51% ± 2.34% of baseline (P < 0.01), and from 38.03% ± 2.34% to 70.12% ± 2.22% of baseline (P < 0.01), respectively. CONCLUSION: Acupuncture at heterotopic acupoints increases the amplitude of jejunal motility in rats. C fibers and M2 receptors predominantly and partially mediate the regulation of jejunal motility by acupuncture, respectively.

[Experimental study on functional connection between the lung and large intestine meridians in the rat: cross-talk between the lung and large intestine meridians].

OBJECTIVE: According to the theory of traditional Chinese medicine about "close association between the lung and the large intestine", the present study was designed to investigate the functional relationship between the Lung and Large Intestine Meridians and the colorectum by using electrophysiological methods. METHODS: A total of 40 SD rats were used in the present study. Under anesthesia, the cardiopulmonary branch of the left sympathetic nerve (CPSN) was separated for recording the electrical activities with a pair of platinum wire electrodes. Intra-colorectal pressure was recorded using a water-balloon inserted into the anus and connected to a pressure-transducer for observing rectocolonic pressure changes (mobility). Electroacupuncture (EA) stimulation was applied to bilateral "Taiyuan" (LU 9)- "Jingqu" (LU 8) of the Lung Meridian, "Yangxi" (LI 5)-"Pianli" (LI 6) of the Large Intestine Meridian, and "Shangjuxu" (ST 37)-"Zusanli" (ST 36) of the Stomach Meridian, respectively. Colorectal distension (CRD, visceral pain stimulation, 60 mmHg and 80 mmHg) was performed using an air-balloon for observing its influence on EA stimulation of LU 9- LU 8 induced changes of electrical activities of CPSN. RESULTS: Under anesthesia conditions, no spontaneous electrical activities of the CPSN were found in rats. After EA stimulation (3 times of the threshold intensity) of the bilateral "Taiyuan" (LU 9)- "Jingqu" (LU 8) of the Lung Meridian, and "Yangxi" (LI 5)-"Pianli" (LI 6) of the Large Intestine Meridian, the evoked discharge numbers of the cardiopulmonary sympathetic nerve were (11.26 +/- 2.34) and (10.73 +/- 2.62) spikes, respectively, without significant differences between the two groups (P > 0.05). Compared with pre-stimulation, the colorectal motility (amplitudes of the intra-colorectal pressure waves) was obviously increased following EA stimulation of LU 9-LU 8 of the Lung Meridian, LI 5-LI 6 of the Large Intestine Meridian and "Shangjuxu" (ST 37)-"Zusanli" (ST 36) , Lower-Ho (Sea) acupoints of the Large Intestine Meridian (P < 0.05). After CRD stimulation at 60 mmHg and 80 mmHg, the LU 9- LU 8-stimulation evoked discharge rates of CPSN were reduced by 43.46% and 67.42%, respectively. CONCLUSION: EA stimulation of LU 9- LU 8 of the Lung Meridian and LI 5-LI 6 of the Large Intestine Meridian can activate discharges of CPSN, and increase the colorectal motility in the rat. CRD stimulation inhibits the activated effect of EA on electrical activities of CPSN. These results show a functional communication or cross-talk between the lung and the colorectum.