Inhibitory effects of melatonin on free intracellular calcium in mouse brain cells.

AIM

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.