Synthesis and release of an acetylcholine-like compound by human myoblasts and myotubes

J Physiol. 1995 Dec 15;489 ( Pt 3)(Pt 3):791-803. doi: 10.1113/jphysiol.1995.sp021092.


1. Exogenously applied acetylcholine (ACh) is a modulator of human myoblast fusion. Using a chemiluminescent method, we examined whether an endogenous ACh-like compound (ACh-lc) was present in, and released by, pure human myogenic cells. 2. Single, freshly isolated satellite cells and proliferating myoblasts contained 15 and 0.5 fmol ACh-lc, respectively. Cultured myotubes contained ACh-lc as well. Also, ACh-like immunoreactivity was detected in all myogenic cells. 3. Part of the ACh-lc was synthesized by choline acetyltransferase (ChAT), as indicated by the reduction of ACh-lc content when bromoACh was present in the culture medium, and by direct measurements of ChAT activity. Also, ChAT-like immunoreactivity was observed in all myogenic cells. 4. Myoblasts and myotubes released ACh-lc spontaneously by a partially Ca(2+)-dependent mechanism. 5. The application by microperfusion of medium conditioned beforehand by myoblasts (thus presumably containing ACh-lc) onto a voltage-clamped myotube induced inward currents resembling ACh-induced currents in their kinetics, reversal potential, and sensitivity to nicotinic antagonists. 6. In vitro, the spontaneously released ACh-lc promoted myoblast fusion but only in the presence of an anticholinesterase. 7. Our observations indicate that human myogenic cells synthesize and release an ACh-lc and thereby promote the fusion process that occurs in muscle during growth or regeneration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / biosynthesis*
  • Acetylcholine / metabolism
  • Adolescent
  • Adult
  • Cell Fusion / physiology
  • Cells, Cultured
  • Child
  • Choline O-Acetyltransferase / metabolism
  • Cholinesterase Inhibitors / pharmacology
  • Clone Cells
  • Flow Cytometry
  • Humans
  • Immunohistochemistry
  • Luminescent Measurements
  • Microtubules / metabolism*
  • Middle Aged
  • Muscle Proteins / metabolism
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / metabolism*
  • Patch-Clamp Techniques
  • Physostigmine / pharmacology


  • Cholinesterase Inhibitors
  • Muscle Proteins
  • Physostigmine
  • Choline O-Acetyltransferase
  • Acetylcholine