Experiments were undertaken on normal subjects at the age of 19-44 years. Pain threshold were measured by Analgesymeter (Made in Ugobasile-Italy) in 60 subjects before and after 30 minutes of PC6 EA. Amplitude and latency of Hoffman wave of 30 males was investigated before and after 30 minutes of PC6 EA. EA parameters were set in 2Hz, 4-5 volts. The following results were shown: (1) PC6 EA could elevate pain threshold in most subjects (p< 0.01); After acupuncture, pain threshold is more increase in women comparing to men (p<0.05). Electric acupunture at Neiguan inhibit H reflex by reduce its amplitude and last the latency of this wave (p<0.05). thse results suggested that pain reduce mechanism of electric accupunture could ralate to the role of nervous system.
Pain Threshold, Electroacupuncture

The purpose of this study was to investigate the effect of electroacuuncture stimulation therapy in the pain threshold of the subjects. 20 patients were randomly assigned to two experimental groups. Measurement of perception and pawn threshold of post-operative patients were taken during 7 days. They were written into preformed formula by themselves. Experiments were peformed with non-acupuncture stimulated group(10 patients) and with acupuncture stimulated group(10 patients). Acupuncture stimulation is applied with 2Hz, 30minutes, 12mA, biphasic wave, combined mix, and bilaterally to meridian points(LI4, CV24, S5 etc). The following results are obtained ; 1. The visual analogue scale of pain threshold was decreased with a time both control and experimental group. 2. The statistical significance was observed between control group and experimental group at 5, 6, 7 days(P<0.05). 3. The Pearson correlation coefficency of experimental group was higher than control group (P<0.05).
Acupuncture ; Electroacupuncture* ; Humans ; Pain Threshold

To research the effects of electroacupuncture on different quantitative parameters on analgesia in rats with adjuvant-induced arthritis. Rats of adjuvant-induced arthritis were treated by electroacupuncture with different waveforms. Pain threshold and swelling degree of joint were observed. Electroacupuncture parameters being selected were measured by frequency spectrum analysis. After treatment, the pain thresholds in the electroacupuncture groups with different waveforms were higher than that of the model group (P < 0.05, P < 0.01); the local swelling degree of inflammation of the electroacupuncture groups were higher than that of the model group (P < 0.01), but was lower than that of the control group (P < 0.05, P < 0.01). Frequency, current, voltage and pulse width of successive wave and intermittent wave were similar. Frequency,current, voltage and pulse width of sound electric wave changed continuously. The results were that all the electroacupuncture with different waveforms had the analgesic effect in rats with adjuvant-induced arthritis and the therapeutic effect of the electroacupuncture of sound electric wave was the best. It is reasonable and important that electroacupuncture parameter should be quantified.
Acupuncture Analgesia ; Animals ; Arthritis, Experimental ; therapy ; Electroacupuncture ; methods ; Female ; Pain Threshold ; Random Allocation ; Rats ; Rats, Wistar

OBJECTIVETo investigate the electrical signals propagated along Foot Taiyang Bladder Meridian (BL) in a rat model.

METHODSThe experiments were performed on Dark-Agouti (DA), DA.1U and Sprague Dawley (SD) rats. The antidromic electrical stimulation was applied on the nerve innervating "Pishu" (BL 20) to mimic the acupoint electro-acupuncture (EA). The activities recording from adjacent nerve innervating acupoint "Danshu" (BL 19) or "Weishu" (BL 21) were recorded as indics for acupoint, including the mechanical threshold and discharge rate.

RESULTSAfter mimic EA on BL 20, C and Aδ units from adjacent BL 19 or BL 21 were sensitized including the decrease in mechanical threshold and increase in discharge rates in DA, DA.1U and SD rats, especially in DA rats. The average discharge rate increased from 2.40±0.26 to 6.06±0.55 and from 1.92±0.42 to 6.17±1.10 impulse/min (P<0.01), and the mechanical threshold decreased from 0.52±0.12 to 0.24±0.05 and from 0.27±0.02 to 0.16±0.01 mmol/L (P<0.01) in C (n=15) and Aδ (n=18) units in DA rats. The net change in discharge rates from C units were 152.5%, 144.7% and 42.4% in DA, DA.1U and SD rats, respectively, among which DA rat's was the highest (P<0.05). In Aδ units, the net change in DA rats were also the highest (221.5%, 139.2% and 49.2% in DA, DA.1U and SD rats).

CONCLUSIONSThese results showed that mimic acupoint EA activated adjacent acupoints along BL in three rat strains, which might be related to propagated sensation along meridians (PSM). In addition, DA rats were more sensitive and might be a good model animal for PSM research.

Acupuncture Points ; Animals ; Electroacupuncture ; methods ; Male ; Meridians ; Pain Threshold ; Rats, Sprague-Dawley ; Urinary Bladder ; innervation

Acupuncture Analgesia ; Animals ; Central Nervous System ; metabolism ; Electroacupuncture ; Nitric Oxide ; metabolism ; Pain Threshold ; physiology ; Rats ; Rats, Wistar

OBJECTIVETo probe into the best parameter of electroacupuncture (EA) for treatment of inflammatory pain in the rat.

METHODSOne hundred and twenty Wistar rats were randomly divided into 12 groups, normal control group, model group and 10 EA groups including A1 B1 C1, A1 B1 C2, A1 B2 C1, A1 B2 C2, A2 B1 C1, A2 B1 C2, A2 B2 C1, A2 B2 C2 (A1 : 2 Hz, A2: 100 Hz; B1 : successive wave; B2: intermittent wave; C1: 0.1 mA, C2: 0.2 mA), A3 B3 C1 (4/20 Hz, disperse-dense wave, 0.1 mA) and A3 B3 C2 (4/20 Hz, disperse-dense wave, 0.2 mA). The rats of adjuvant-induced arthritis in all of the EA groups were treated by EA with selected different parameters once every day for 6 days. Pain thresholds and beta-endorphin (beta-EP) content in the local tissue of inflammation were used as indexes to compare analgesic effects of EA of different frequencies, waveforms and currents by orthogonal experiment design and other methods.

RESULTSThe optimized parameters of raising the pain threshold was: 100 Hz, 0.1 mA, intermittent wave. EA at 100 Hz was better than 2 Hz for increasing the content of beta-EP in local tissue of inflammation. The analgesic effect of EA at 4/20 Hz, 0.1 mA, disperse-dense wave on the inflammatory pain in the rat was not significant different with that at 100 Hz, 0.1 mA, intermittent wave (P > 0.05).

CONCLUSIONThe best parameters are 100 Hz, 0.1 mA and intermittent wave for EA treatment of inflammatory pain in the rat.

Acupuncture Analgesia ; Animals ; Arthritis ; metabolism ; physiopathology ; therapy ; Electroacupuncture ; Female ; Humans ; Pain ; metabolism ; physiopathology ; Pain Management ; Pain Threshold ; Random Allocation ; Rats ; Rats, Wistar ; beta-Endorphin ; metabolism

OBJECTIVETo observe the effect of electroacupuncture (EA) on pain threshold and spinal NR2B subunit expression in a rat model of neuropathic pain due to chronic compression injury (CCI) of the sciatic nerve and explore the analgesic mechanism of EA.

METHODSMale SD rats weighing 200-280 g were randomly divided into 4 groups (n=10), namely the sham-operated group, CCI group, EA+CCI group, and sham EA+CCI group. All the rats underwent tests of the mechanical withdrawal threshold and thermal threshold. On day 13 after the surgery, all the rats were decapitated to collect the L4-6 segments of the spinal cord to examine NR2B expression using Western blotting.

RESULTSThe postoperative mechanical withdrawal threshold and thermal threshold were significantly lowered in CCI, EA+CCI and sham EA+CCI groups as compared to those before the surgery (P<0.05). EA obviously alleviated the hypersensitivity in the rats with CCI and inhibited spinal NR2B expressions (P<0.05). No significant differences were found in the mechanical withdrawal threshold, thermal threshold or spinal NR2B subunit expression between CCI group and sham EA+CCI group (P>0.05).

CONCLUSIONEA may alleviate neuropathic hypersensitivity partially by inhibiting NR2B expression in the spinal cord of rats with neuropathic pain resulting from CCI of the sciatic nerve.

Animals ; Electroacupuncture ; Male ; Neuralgia ; metabolism ; pathology ; therapy ; Pain Threshold ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Spinal Cord ; metabolism

Electroacupuncture (EA) is a modified form of acupuncture that utilizes electrical stimulation. We previously showed that EA stimulated rats were divided into responders that were sensitive to EA and non-responders that were insensitive to EA based on the tail flick latency (TFL) test. The dopamine beta-hydroxylase (DBH) gene was more abundantly expressed in the hypothalamus of responder rats than non-responder rats. To determine whether overexpression of DBH gene expression in the hypothalamus modulate EA analgesia, we constructed a DBH encoding adenovirus and which was then injected into the hypothalamus of SD rats. Microinjection of DBH or control GFP virus into the hypothalamus had no changes on the basal pain threshold measured by a TFL test without EA treatment. However, the analgesic effect of EA was significantly enhanced from seven days after microinjection of the DBH virus, but not after injection of the control GFP virus. DBH expression was significantly higher in the hypothalamus of DBH virus injected rat than control GFP virus or PBS injected rats. Moreover, expression of the DBH gene did not affect the body core temperature, body weight, motor function or learning and memory ability. Although the functional role of DBH in the hypothalamus in the analgesic effect of EA remains unclear, our findings suggest that expression of the DBH gene in the hypothalamus promotes EA analgesia without obvious side-effects.
Acupuncture ; Adenoviridae ; Analgesia* ; Animals ; Body Temperature ; Dopamine beta-Hydroxylase* ; Dopamine* ; Electric Stimulation ; Electroacupuncture* ; Gene Expression ; Hypothalamus* ; Learning ; Memory ; Microinjections ; Pain Threshold ; Rats* ; Viruses

BACKGROUND/AIMS: While it is well established that acupuncture relieves somatic pain, its therapeutic effect on visceral pain such as irritable bowel syndrome (IBS) is unclear. We evaluated the effect of acupuncture in treating visceral hyperalgesia in an animal model. METHODS: Sprague-Dawley rats (n = 8 per group) with prior neonatal maternal separation stress were randomly allocated to receive 3-day treatment of either electroacupuncture (EA) or sham acupuncture at acupoint ST-36. Another group of rats without prior maternal separation was included as non-handled controls. Colorectal distension was performed on the day after acupuncture treatment. The 3 groups were compared for pain threshold as determined by abdominal withdrawal reflex and visceromotor response as measured by electromyogram. Colon, spinal cord, and brainstem were sampled for topographic distribution and quantitative assessment of serotonin and Fos expression by immunohistochemistry. RESULTS: Rats in EA group had significantly higher pain threshold compared to those in sham acpuncture group (25.0 +/- 5.7 mmHg vs 18.7 +/- 5.2 mmHg, p = 0.01) and it was comparable with that of non-handled treatment naive controls (29.4 +/- 9.3 mmHg, p = 0.28). They also had lower visceromotor response as measured by electromyogram compared to those received sham acupuncture at all colorectal distension pressures. EA significantly suppressed Fos expression in doral raphe nuclei of brainstem, superficial dorsal horn of spinal cord and colonic epithelium but suppressed 5-HT expression only in brainstem and spinal cord. CONCLUSIONS: Electro acupuncture attenuates visceral hyperlagesia through down-regulation of central serotonergic activities in the brain-gut axis.
Acupuncture ; Acupuncture Points ; Animals ; Axis, Cervical Vertebra ; Benzodiazepines ; Brain Stem ; Colon ; Down-Regulation ; Electroacupuncture ; Epithelium ; Horns ; Hyperalgesia ; Immunohistochemistry ; Irritable Bowel Syndrome ; Models, Animal ; Nociceptive Pain ; Pain Threshold ; Raphe Nuclei ; Rats ; Rats, Sprague-Dawley ; Reflex ; Salicylamides ; Serotonin ; Spinal Cord ; Visceral Pain

To observe the effect of multiple electroacupuncture (EA) on the pain threshold and the regulation of N-methyl-D-aspartate (NMDA) receptor in dorsal root ganglia (DRG) of neuropathic pain rats. Rats were prepared with a unilateral chronic constriction injury (CCI) to the sciatic nerve. EA was done in acupoints "Huan Tiao" and "Yang Ling Quan" for 30 min every day and the thermal thresholds were detected after EA at 3, 5, 7, 10, 14 days after operation. On day 14 after nerve injury, the in situ hybridization method was used to investigate the change of NMDA R1 mRNA in L4-L5 DRG. The thermal threshold reduced significantly from day 3 after operation in CCI rats. After multiple EA treatment, the ipsilateral thermal hyperalgesia relieved gradually and the thermal threshold had no difference with control side after day 5 (P > 0.05). From Day 7 after operation, the thermal threshold at each time point were significantly different compared with CCI group respectively (P > 0.05). Moreover the EA had accumulative effect. On Day 14 after operation, the NMDAR1 mRNA positive neurons and the mean optic density in ipsilateral L4-5 DRG were less than that of control side (P < 0.05), mainly in medium and small neurons. After EA treatment, the NMDAR1 mRNA positive neurons in ipsilateral DRG had no considerable difference comparing with those of control side, significantly increased comparing with CCI group (P < 0.05). It's concluded that the NMDA receptors in DRG relate closely with the generation and development of neuropathic pain. The multiple EA treatment can attenuate the thermal hyperlagesia of neuropathic pain rats and regulate the NMDA receptor.
Animals ; Electroacupuncture ; Ganglia, Spinal ; metabolism ; Hyperalgesia ; physiopathology ; Male ; Neuralgia ; metabolism ; physiopathology ; Pain Measurement ; Pain Threshold ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; biosynthesis ; genetics ; Sciatic Nerve