A role for cAMP in the development of functional neuromuscular transmission.
We have found that the incidence of functionally connected neuron-myotube pairs in chick ciliary-myotube cultures increases from 58% to more than 90% when the cells are treated for several hours with 8-bromo-cyclic adenosine monophosphate (8-br-cAMP) or with agents known to increase intracellular cAMP. The increase in connectivity was not accompanied by a change in neuron survival, or in the length of neurite-myotube contact. Moreover, there was no change in the shape of the presynaptic action potential, in mean end plate potential (epp) amplitude or in the sensitivity of postsynaptic acetylcholine receptors (AChRs). One interpretation of these results in that a cAMP-dependent phosphorylation acts as a trigger to activate a previously "silent" synapse.
Dubinsky
J M
JM
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110.
Fischbach
G D
GD
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D002645:Chickens; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D005726:Ganglia, Parasympathetic / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009132:Muscles / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000378:metabolism; D009435:Synaptic Transmission
D011950:Receptors, Cholinergic; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000242:Cyclic AMP; D000109:Acetylcholine