title: Role of glycogenolysis in stimulation of ATP release from cultured mouse astrocytes by transmitters and high K+ concentrations.
abstract: This study investigates the role of glycogenolysis in stimulated release of ATP as a transmitter from astrocytes. Within the last 20 years our understanding of brain glycogenolysis has changed from it being a relatively uninteresting process to being a driving force for essential brain functions like production of transmitter glutamate and homoeostasis of potassium ions (K+) after their release from excited neurons. Simultaneously, the importance of astrocytic handling of adenosine, its phosphorylation to ATP and release of some astrocytic ATP, located in vesicles, as an important transmitter has also become to be realized. Among the procedures stimulating Ca2+-dependent release of vesicular ATP are exposure to such transmitters as glutamate and adenosine, which raise intra-astrocytic Ca2+ concentration, or increase of extracellular K+ to a depolarizing level that opens astrocytic L-channels for Ca2+ and thereby also increase intra-astrocytic Ca2+ concentration, a prerequisite for glycogenolysis. The present study has confirmed and quantitated stimulated ATP release from well differentiated astrocyte cultures by glutamate, adenosine or elevated extracellular K+ concentrations, measured by a luciferin/luciferase reaction. It has also shown that this release is virtually abolished by an inhibitor of glycogenolysis as well as by inhibitors of transmitter-mediated signaling or of L-channel opening by elevated K+ concentrations.
authors: *Department of Clinical Pharmacology, China Medical University, Shenyang, P. R. China.
authors: Junnan
authors: J
authors: Xu
authors: *Department of Clinical Pharmacology, China Medical University, Shenyang, P. R. China.
authors: Dan
authors: D
authors: Song
authors: *Department of Clinical Pharmacology, China Medical University, Shenyang, P. R. China.
authors: Qiufang
authors: Q
authors: Bai
authors: *Department of Clinical Pharmacology, China Medical University, Shenyang, P. R. China.
authors: Lijun
authors: L
authors: Zhou
authors: †Laboratory of Molecular Biology, Liaoning University of Traditional Chinese Medicine, Shenyang, P. R. China.
authors: Liping
authors: L
authors: Cai
authors: *Department of Clinical Pharmacology, China Medical University, Shenyang, P. R. China.
authors: Leif
authors: L
authors: Hertz
authors: *Department of Clinical Pharmacology, China Medical University, Shenyang, P. R. China.
authors: Liang
authors: L
authors: Peng
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D002478:Cells, Cultured; D018698:Glutamic Acid / Q000378:metabolism; D050261:Glycogenolysis / Q000502:physiology*; D008163:Luminescent Measurements; D051379:Mice; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*
chemical_list: D018377:Neurotransmitter Agents; D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D011188:Potassium