title: Regulation of development in Dictyostelium discoideum. IV. Effects of ions on the rate of differentiation and cellular response to cyclic AMP.
abstract: The effects of ionic environment on both the intrinsic rate of differentiation and the response to exogenous cyclic AMP in Dictyostelium discoideum have been examined. K+ specifically inhibits the rate of early development when present at concentrations > 15 mM. Na+ does not inhibit at concentrations up to 25 mM, and can partially overcome K+ inhibition. The maximum rate of development also depends upon the presence of adequate levels of extracellular Ca++. The effect of exogenous cyclic AMP on the rate of development is inhibited by the absence of Ca++, and/or the presence of high concentrations of K+. Under optimal ionic conditions, the only effect of exogenous cyclic AMP on early developments of K+. Under optimal ionic conditions, the only effect of exogenous cyclic AMP on early development is a specific inhibition. The implications of these results for current models of early developmental regulation are discussed.
mesh_terms: D002021:Buffers; D002118:Calcium / Q000494:pharmacology*; D000242:Cyclic AMP / Q000494:pharmacology*; D004023:Dictyostelium / Q000187:drug effects / Q000254:growth & development*; D011188:Potassium / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology*
chemical_list: D002021:Buffers; D012964:Sodium; D000242:Cyclic AMP; D011188:Potassium; D002118:Calcium