Inhibitory effects of melatonin on free intracellular calcium in mouse brain cells.
OBJECTIVE
To study the effects of melatonin (Mel) on cortical intrasynaptosomal calcium concentration in old mice and on [Ca2+]i elevation induced by Bay-K-8644, KCl, and sodium l-glutamate in isolated brain cells of neonatal mouse, and to determine the antiaging mechanism of Mel.


METHODS
[Ca2+]i was measured in an RF-5000 recording spectrofluorophotometer by preloading the synaptosomes or cells with Fura 2-AM.


RESULTS
Long term of administrating Mel inhibited the overload of [Ca2+]i in old mouse cerebral cortex. The [Ca2+]i in both high (20 mg.L-1) and low dose (1 mg.L-1) of Mel groups was reduced from (434 +/- 32) nmol. L-1 (the older control group) to (330 +/- 41) and (313 +/- 56) nmol.L-1, respectively, P < 0.01. Mel 0.01, 0.1, 1, and 3 mumol.L-1 remarkably reduced [Ca2+]i elevations in isolated newborn mouse brain cells induced by Bay-K-8644, KCl, and Glu.


CONCLUSIONS
The inhibitory effect of Mel on neuronal [Ca2+]i overload is involved in its antiaging effect.
Zhang
Q Z
QZ
Second Department of Pharmacology, Chinese Academy of Medical Sciences, Beijing, China. zjtian@public.bta.net.cn
Zhang
J T
JT
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000037:antagonists & inhibitors; D000375:Aging / Q000187:drug effects*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D005260:Female; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D011189:Potassium Chloride / Q000037:antagonists & inhibitors; D011897:Random Allocation; D012970:Sodium Glutamate / Q000037:antagonists & inhibitors
D002121:Calcium Channel Blockers; D011189:Potassium Chloride; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D008550:Melatonin; D002118:Calcium; D012970:Sodium Glutamate