Extracellular magnesium regulates intracellular free Mg2+ in vascular smooth muscle cells.
Regulatory effects of extracellular magnesium ions ([Mg2+]o) on intracellular free ionized magnesium ([Mg2+]i) were examined in cultured vascular smooth muscle cells (VSMCs) from rat aorta by digital imaging microscopy using the Mg2+ fluorescent probe, Mag-fura-2. With normal Mg2+ (1.2 mM)-containing incubation media, [Mg2+]i in VSMCs was 0.63 +/- 0.09 mM. The ratio of [Mg2+]i/[Mg2+]o was 0.52 +/- 0.07. Elevation of [Mg2+]o up to 4.8 mM induced consistent increments in [Mg2+]i (to a mean values of 1.63 +/- 0.08 mM) in 5 min and lowered the ratio of [Mg2+]i/[Mg2+]o to 0.34 +/- 0.02. Our data suggest that [Mg2+]o can regulate [Mg2+]i, which may be related to its effects on intracellular Ca2+ ([Ca2+]i) and tone of VSMCs.
Zhang
A
A
Department of Physiology, State University of New York, Brooklyn 11203.
Cheng
T P
TP
Altura
B T
BT
Altura
B M
BM
D000818:Animals; D001011:Aorta; D017136:Ion Transport; D008274:Magnesium / Q000032:analysis* / Q000494:pharmacology / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000737:chemistry* / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar
D008274:Magnesium