Table 1.
Regulatory effects of acupuncture on afferent fibers activity.
| References | Model | Intervention methods | Acupoints | Acupuncture parameters | Effect measurements | Afferent fibers activity regulated by acupuncture |
|---|---|---|---|---|---|---|
| Lee J. H. et al. (2020) | Oxaliplatin injection | BV | ST36 | Subcutaneous injection | Cold and mechanical allodynia ↑ | Current Threshold for Action Potential Generation in A Fiber DRG Neurons ↑ |
| Gao et al. (2015) | Diarrhea or constipation | MA | LI11, ST37, BL25, ST25 | 2 Hz, rotated right then left about 180°, 60 s | Colonic motility ↑ | Activation of C fiber ↑ |
| Qin et al. (2014) | Diarrhea or constipation | MA | LI11, ST37, BL25, ST25 | 2 Hz, rotated right then left about 180°, 60 s | Jejunal motility ↑, Intrajejunal pressure ↓, Constipation or diarrhea frequency↓ | Activation of C fiber ↑ |
| Hino et al. (2010) | Irritated bladder | Sacral acupuncture | Periosteum of the sacral segment | Rotated manually 1.0–1.5 turns per second for 1 min turns per second for 1 min | Intercontraction interval ↑ | Capsaicin-sensitive C fiber activation ↓ |
| Xin et al. (2016) | ASIC3 gene knockout TRPV1 gene knockout | EA | ST36 | 50 Hz, 20 min | Mechanical pain thresholds ↓, Thermal pain thresholds ↓ | After gene knockout, intensity on C-fiber reflex ↓ |
| Fan et al. (2021) | Hypertension | MA | PC6, SI5 | 20 Hz at 1 min-intervals, 10 min | WDR ↑, Single fiber recordings ↑ | Sensitivity of both somatic A and C fibers ↑ |
| Guo et al. (2018) | Gastric distension | MA, EA | ST36, PC5, PC6, BL40 | MA 2 Hz, EA 2 Hz 0.3–0.5 mA, 0.5 ms duration | Von Frey hairs threshold ↓ | After TRPV1 blockade afferent fiber activity↓ |
| Duanmu et al. (2020) | CFA | EA, TENS | ST34 | 2 Hz/100 Hz, 1 ms wave width, 30 min, 3 days | Abnormal electromyography ↓ | In thresholds of A and C, abnormal electromyography ↓ |
| Chen et al. (2021) | CFA | MA, EA | BL57 | MA at a depth of 2 mm for 10 min; EA 10 Hz, 0.2 ms, 1 mA | Difference score of weight-bearing ↑ | Muscular A fibers activity ↑ in deep EA Cutaneous C fibers activity ↑ in MA |
| Song et al. (2021) | CFA | MA | ST36, BL60 | 2 r/s, 4 r/s, 1 min, 7 days | Paw withdrawal latency ↑ | Activates of C fibers ↑ in 4 r/s MA |
| Duan-Mu et al. (2021) | CFA | EA | ST34 | 2/100 Hz, 30 min | LTM Neurons ↑, WDR Neurons ↓ | Spontaneous firing of LTM neurons ↑ WDR neurons ↓ by EA with intensity of threshold of A fibers |
| Xue et al. (2020) | Spared nerve injury | EA | ST36, SP6 | 2 Hz, 0.6 ms pulse width 10 min, 14 days | TrκB mRNA ↓, Mechanical hypersensitivity ↓ | C fiber-evoked discharges of WDR neurons in the spinal dorsal horn ↓ |
| Qu et al. (2020) | Acute migraine | EA | GB8, GB2 | 0.5 ~ 1 mA, 2 ~ 15 Hz | Mechanical pain threshold ↓, WDR neuronal spikes ↓ | C fiber evoked WDR neuronal discharges of the trigeminocervical complex ↓ |
| Ma et al. (2009) | Neuropathic pain | EA | GB30, BL40 | 1 Hz, 30 mA, 7 min, 2 days | Mechanical pain threshold ↑ | C fiber high-frequency-stimulation induced LTP ↓ |
| Li et al. (2019) | Postherpetic neuralgia | EA | GB30, GB34 | 1 mA, 30 min | Netrin-1↓, UNC5H2 ↑, Mechanical thresholds ↑ | Resiniferatoxin-induced myelinated primary afferent nerve fiber sprouting into the spinal cord lamina II ↓ |
| Wu et al. (2013) | Postherpetic neuralgia | EA | GB30, GB34 | 1 mA and 0.1 ms, 2 and 15 Hz, once every other day | Paw withdrawal thresholds ↑ | Myelinated afferent nerves and their abnormal sprouting into the spinal lamina II ↓ |
| Dai et al. (2019) | Incision pain | EA | SP6, GB34 | Pulse width: 0.2 ms, intensities ranging 1–2-3 mA and each intensity for 10 min | Mechanical allodynia ↓ | LTP of C fiber-evoked potentials in the spinal cord ↓ |
| Peng et al. (2019) | Normal female | TENS | Radial nerve | 100 Hz, 4 Hz TENS, 30 min | Alpha electroencephalography ↑ | Aδ and C cutaneous nociceptors ↑ by low-frequency and high-intensity TENS |
| Liu et al. (2011) | Visceral pain | EA | ST2, GB14 | 2 Hz, 20 Hz, 1–5 mA | Abdominal contractions↓, C-fos expressions in NTS↓, in PTN↑ | Aδ and C fibers c-fos expression ↑ in NTS |
| Li Y. Q. et al. (2007) | Normal rat | EA | ST13, LI11, CV6, ST21, ST36, ST21, BL21 | 0.8 and 2 thresholds for the activation of Aδ fiber, 1.5 threshold for the activation of C fiber, 30 s | Gastric motility response ↑ in Aδ fiber reflex threshold, ↓ in C fiber reflex threshold | Activation of Aδ afferent fibers ↑ in Aδ fiber reflex threshold Activation of C afferent fibers ↑ in C fiber reflex threshold |