Acetylcholine may regulate its own nicotinic receptor-channel through the C-kinase system.
Acetylcholine (ACh)-activated channel properties were examined on an aneural culture of chick embryo myotubes by using patch-clamp techniques. Changes in conductance, open time and closed time were induced by the selective activator of the calcium- and phospholipid-dependent C-kinase (PKc), 12-O-tetradecanoylphorbol-13-acetate (TPA). The action of TPA was mimicked by exogenous phospholipase C and was blocked by the PKc inhibitor, 1-(5-isoquinolinylsulphonyl)-2-methyl-piperazine. In addition to its gating action, ACh was shown to stimulate phosphoinositide turnover and to translocate PKc from the cytosol to the cell membrane. Both these ACh-induced effects were inhibited by curare and not substantially affected by atropine. Bath-applied ACh outside the patch-pipette in the cell-attached patch-clamp mode, had a strong effect on the ACh-activated channels in the patch membrane, in a way that resembled the action of TPA. These findings raise the possibility that ACh regulates its own nicotinic receptors through the C-kinase system.
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D002642:Chick Embryo; D003600:Cytosol / Q000201:enzymology; D009132:Muscles / Q000201:enzymology / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology*; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D011978:Receptors, Nicotinic; D001285:Atropine; D011493:Protein Kinase C; D000109:Acetylcholine; D013755:Tetradecanoylphorbol Acetate