Temperature and nitric oxide control spontaneous calcium transients in astrocytes.
Transient spontaneous increases in the intracellular Ca2+ concentration have been frequently observed in astrocytes in cell culture and in acutely isolated slices from several brain regions. Recent in vivo experiments, however, reported only a low frequency of spontaneous Ca2+ events in astrocytes. Since the ex vivo experiments were usually performed at temperatures lower than physiological body temperature, we addressed the question whether temperature could influence the spontaneous Ca2+ activity in astrocytes. Indeed, comparing the frequency and spike width of spontaneous Ca2+ transients in astrocytes at temperatures between 20 and 37 degrees C in culture as well as in acute cortical slices from mouse brain, revealed that spontaneous Ca2+ responses occurred frequently at low temperature and became less frequent at higher temperature. Moreover, the single Ca2+ events had a longer duration at low temperature. We found that nitric oxide (NO) mimicked the increase in spontaneous Ca2+ activity and that an NO-synthase inhibitor attenuated the effect of lowering the temperature. Thus, temperature and NO are major determinants of spontaneous astrocytic Ca2+ signalling.
Schipke
Carola G
CG
Charité University Medicine Berlin, Department of Psychiatry and Psychotherapy, CBF, Eschenallee 3, 14050 Berlin, Germany.
Heidemann
Antje
A
Skupin
Alexander
A
Peters
Oliver
O
Falcke
Martin
M
Kettenmann
Helmut
H
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010477:Perfusion; D026422:S-Nitrosoglutathione / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione