title: Acupuncture at heterotopic acupoints facilitates distal colonic motility via activating M3 receptors and somatic afferent C-fibers in normal, constipated, or diarrhoeic rats.
abstract: BACKGROUND
  Previous studies have demonstrated the efficacy of somatic stimulation for patients with gastrointestinal motility disorders. However, little effort has been made to investigate the effects of acupuncture on colonic motility, particularly in pathological conditions. The precise mechanism employed in the regulation of acupuncture on colonic motility still remains unclear.
  
  
  METHODS
  We assessed the effect of acupuncture at heterotopic acupoints on distal colonic motility using a warm-water-filled manometric balloon inserted 5-6 cm into the rectum of anesthetized normal rats or rats with diarrhea or constipation. Choline chloride, 4-DAMP, cobra venom and capsaicin were separately applied to investigate the role of M3 receptors in the regulation of distal colonic motility by acupuncture at heterotopic acupoints, and whether Aδ- and/or C-fibers are required for triggering distal colonic motility by acupuncture.
  
  
  RESULTS
  Acupuncture at heterotopic acupoints increased distal colonic motility not only in normal rats but also in rats with constipation or diarrhea. M3 receptors play an important role in the facilitation of distal colonic motility triggered by acupuncture at heterotopic acupoints. Afferent nerve Aδ- and C-fibers mediate the transduction of the acupuncture signal and C-fibers are essential for enhancing the effect of acupuncture at the heterotopic acupoint on distal colonic motility.
  
  
  CONCLUSIONS
  Our results reveal that acupuncture at heterotopic acupoints increases distal colonic motility regardless of normal or pathological conditions via predominately activating C-fibers of somatic afferent nerve and M3 receptors.
authors.affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
authors.forename: X
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.|Department of Acupuncture and Moxibustion, Henan Orthopedics Hospital, Luoyang, Henan Province, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Qin
authors.affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
authors.forename: X
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
authors.forename: K
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.|Third Clinical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China.|Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, USA.
authors.forename: H
authors.initials: H
authors.lastname: Qiao
authors.affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
authors.forename: B
authors.initials: B
authors.lastname: Zhu
mesh_terms: D015669:Acupuncture Points; D015670:Acupuncture Therapy; D000818:Animals; D003106:Colon / Q000502:physiology*; D003248:Constipation / Q000378:metabolism; D003967:Diarrhea / Q000378:metabolism; D004195:Disease Models, Animal; D004594:Electrophysiology; D005769:Gastrointestinal Motility / Q000502:physiology*; D008297:Male; D008365:Manometry; D036421:Nerve Fibers, Unmyelinated / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043587:Receptor, Muscarinic M3 / Q000378:metabolism*
chemical_list: D043587:Receptor, Muscarinic M3
keywords: C-fibers; M3 receptors; acupuncture; colonic motility; heterotopic acupoints