Involvement of K(+) channels in the inhibitory effects of adenosine on anoxia-induced [Ca(2+) ](i) increase in cultured rat hippocampal CA1 neurons.
Changes in intracellular free Ca(2+) concentration ([Ca(2+)](i)) in cultured hippocampal CA1 neurons isolated from newborn rats were measured by a confocal laser scanning microscope, using the Ca(2+) indicator Fluo-3. The results showed that exogenous adenosine (100 microM) significantly attenuated the increase of neuronal [Ca(2+)](i) induced by acute anoxia. This effect of adenosine could be suppressed by the adenosine A1 receptor antagonist 8-cyclopentyltheophylline. Moreover, potassium channel blockers, aminopyridine, and glipizide could also block the inhibitory role of adenosine, but tetraethylammonium had no effect. These results suggest that adenosine may activate 4-AP or ATP-sensitive potassium channels via an A1-receptor-mediated mechanism and consequently inhibit anoxia-induced [Ca(2+)](i) elevation in hippocampal neurons.
Wan
Q
Q
Department of Neurobiology, Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing, China.
Yao
H
H
Wang
F
F
D015761:4-Aminopyridine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005913:Glipizide / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D000860:Hypoxia / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D009994:Osmolar Concentration; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D019789:Tetraethylammonium / Q000494:pharmacology
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D019789:Tetraethylammonium; D015761:4-Aminopyridine; D000241:Adenosine; D002118:Calcium; D005913:Glipizide