3 to 5 days‐old embryonic rat skeletal muscle cells (myotubes) present electrically‐induced [CA2+]ii transients uncoupled to any measurable contraction (quiescent myotubes). Acetylcholine (10−5M) induces a transient variation of [Ca2+]iwhose spatial maps, at the beginning of the oscillation, is similar to electrically and caffeine‐induced [Ca2+]itransients. Later (after 1 sec), the spatial distribution of [Ca2+]iis modified, suggesting a different mechanism undering the [Ca2+]iincrease.