[Effect of melatonin on the spatial and temporal changes of [Ca2+]i in single living cells of cortical neurons by laser scanning confocal microscopy].
OBJECTIVE
To examine the effects of melatonin on the dynamic changes in the concentration of intracellular free Ca2+ ([Ca2+]i) in single intact cultured cortical neurons isolated from fetal rats, in order to explore the possible antiaging mechanisms of melatonin (MT).


METHODS
Using the highly fluorescent Ca(2+)-sensitive indicator Fluo-3/AM, cortical neurons cultured in a 35 mm Tissue Culture Dish were in incubated for 45 min at room temperature with 5 mumol/L Fluo-3/AM, resulting in proper intracellular dye concentration to provide adequate signal strength for detection and excellent Laser Scanning Confocal Microscopy (LSCM) imaging of [Ca2+]i while not disturbing normal intracellular physiology. The changes in fluorescent intensity were monitored by LSCM.


RESULTS
Bay K8644 (10(-6) mol/L), KCl (20 mmol/L), sodium L-glutamate (Glu, 50 mumol/L) caused a rapid increase of [Ca2+]i in cortical neurons, and this increase could be significantly attenuated by 10(-6) and 10(-7) mol/L MT.


CONCLUSIONS
MT could antagonize the extracellular Ca2+ influx, reduce Ca2+ overload, and have a protective effect on neurons. This may be one of the important antiaging mechanisms of MT.
Zhang
Q
Q
Department of Pharmacology II, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China.
Zhang
J
J
D000375:Aging / Q000187:drug effects*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D008550:Melatonin / Q000494:pharmacology*; D018613:Microscopy, Confocal; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D008550:Melatonin; D002118:Calcium