title: Transmitter-like action of ATP on patched membranes of cultured myoblasts and myotubes.
abstract: The concept of purinergic neurotransmission, first proposed by Burnstock, has been confirmed in various cell types. We show here, by the patch-clamp method, that external ATP in micromolar concentrations (1-100 microM) activates cation channels in the membranes of fusion-competent myoblasts and myotubes. In cell-attached membrane patches of myoblasts and myotubes the mean number of simultaneously activated channels increases with time after external ATP application. In myoblasts only one population of channels having a mean single-channel conductance of gamma=43 pS was found, while in myotubes two populations with gamma 1=48 pS and gamma 2=20 pS were observed. Treatment of myotube membranes with acetylcholine (ACh) or carbachol resulted in two populations of channels which had conductance values and voltage-dependent mean channel lifetimes similar to those produced in response to ATP. The results show that embryonic skeletal muscle cells contain cation channels sensitive to ATP and provide evidence for a neurotransmitter-like action of ATP on these cells.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000196:embryology / Q000502:physiology*
chemical_list: D007473:Ion Channels; D000255:Adenosine Triphosphate