Biomaterial Database

Oscillations and cyclic AMP-induced changes of the K+ concentration in Dictyostelium discoideum. 1985

S Aeckerle, and B Wurster, and D Malchow

By means of a K+-sensitive electrode, the extracellular K+ concentration was monitored in cell suspensions of Dictyostelium discoideum. In aggregative cells the attractant cyclic AMP induced a transient release of K+. The response was detectable within 6-12 s and peaked at 30-40 s. The apparent rate of release amounted to 7 X 10(8)K+ ions per cell per min. Adenosine and 5' AMP, which are chemotactically inactive, did not elicit measurable K+ responses. The cyclic AMP-induced release of K+ depended on the state of differentiation of the cells. In undifferentiated cells cyclic AMP did not cause a measurable K+ release, whereas folic acid, a potent attractant at this cell stage, induced a weak but significant K+ response. The cyclic AMP-induced K+ release in aggregative cells was inhibited by K+-channel blockers such as quinine and tetraethylammonium. In suspensions of differentiated cells free running oscillations of the extracellular K+ concentration were observed. K+ oscillations were related to cyclic AMP oscillations and oscillations of the light-scattering properties of cells. Cells continuously released NH4+; however, cyclic AMP did not induce a measurable change of NH4+ release.

UI	MeSH Term	Description	Entries
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004023	Dictyostelium	A genus of protozoa, formerly also considered a fungus. Its natural habitat is decaying forest leaves, where it feeds on bacteria. D. discoideum is the best-known species and is widely used in biomedical research.	Dictyostelium discoideum,Dictyostelium discoideums,Dictyosteliums,discoideum, Dictyostelium
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000641	Ammonia	A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.