Lack of effect of transmembrane gradient of magnesium and sodium on regulation of cytosolic free magnesium concentration in rat lymphocytes.
The regulation of the intracellular concentration of Mg2+ ([Mg2+]i) is not fully understood. The level of Mg in lymphocytes is a good predictor of total body Mg status. We measured [Mg2+]i and total Mg in rat lymphocytes by using, respectively, the fluorescent Mg2+ indicator mag-fura-2 and atomic absorption spectrophotometry. The basal [Mg2+]i in rat lymphocytes was 328 +/- 23 micromol/l. An elevation to 5 mmol/l or the removal of extracellular Mg2+ did not affect [Mg2+]i. A reduction in extracellular Na+ did not influence [Mg2+]i for 60 min. The total Mg concentration in lymphocytes also remained stable. Results suggest that the permeability of the plasma membrane to Mg2+ is very low, and that Na+/Mg2+ exchange is not involved in the regulation of [Mg2+]i in rat lymphocytes.
Sasaki
N
N
First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
Oshima
T
T
Matsuura
H
H
Yoshimura
M
M
Yashiki
M
M
Higashi
Y
Y
Ishioka
N
N
Nakano
Y
Y
Kojima
R
R
Kambe
M
M
Kajiyama
G
G
D000818:Animals; D002463:Cell Membrane Permeability; D003600:Cytosol / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D016257:Fura-2 / Q000031:analogs & derivatives / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism*; D008274:Magnesium / Q000097:blood* / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000494:pharmacology*; D013054:Spectrophotometry, Atomic
D005456:Fluorescent Dyes; C058776:2-(2-(5-carboxy)oxazole)-5-hydroxy-6-aminobenzofuran-N,N,O-triacetic acid; D012964:Sodium; D008274:Magnesium; D016257:Fura-2