Abstract
Exogeneous cyclic AMP (cAMP, 10−8M), when added together with acetylcholine (ACh, 500 μM) to dissociated chick embryo cells, blocked the ACh-stimulated increase in the level of cytosolic free Ca2+ ([Ca2+]i). This inhibiting action of exogeneous cAMP is probably mediated by intracellular cyclic GMP (cGMP) and cAMP.