Irreversible inhibition of phospholipid methylation and protein carboxymethylation does not alter acetylcholine receptor function in muscle cells

Exp Neurol. 1984 Nov;86(2):198-207. doi: 10.1016/0014-4886(84)90181-x.


The role of methyltransferase (MT) reactions in acetylcholine (ACh)-evoked depolarization and contraction in primary chick myotubes was determined by using a mixture of erythro-9-(2-hydroxy-3-nonyl) adenine, homocysteine thiolactone, and adenosine which together inhibit the activity of MT. Carboxy-MT and lipid-MT activities were inhibited irreversibly by 91 and 100%, respectively. ACh-induced muscle contraction was also inhibited within 10 min after application of the inhibitor mixture. However, in contrast to permanent inhibition of MT activities, inhibition of acetylcholine receptor (AChR)-dependent muscle contraction was reversible. Moreover, physiological studies showed that the inhibitor mixture had no effect on resting membrane potential or ACh-induced depolarization or desensitization. These results suggest that AChR function is not altered by methylation inhibitors and that changes in AChR-mediated contraction are not due to inhibition of MT activities.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylcholine / pharmacology
  • Acetylcholine / physiology
  • Animals
  • Carboxy-Lyases / metabolism
  • Cells, Cultured
  • Chick Embryo
  • Electric Conductivity
  • Methylation
  • Methyltransferases / antagonists & inhibitors
  • Methyltransferases / metabolism
  • Muscle Contraction / drug effects
  • Muscle Proteins / metabolism*
  • Muscles / cytology
  • Muscles / metabolism*
  • Muscles / physiology
  • Phospholipids / metabolism*
  • Receptors, Cholinergic / physiology*


  • Muscle Proteins
  • Phospholipids
  • Receptors, Cholinergic
  • Methyltransferases
  • Carboxy-Lyases
  • Acetylcholine