title: Lack of effect of transmembrane gradient of magnesium and sodium on regulation of cytosolic free magnesium concentration in rat lymphocytes.
abstract: 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.
authors.affiliation: First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Oshima
authors.forename: H
authors.initials: H
authors.lastname: Matsuura
authors.forename: M
authors.initials: M
authors.lastname: Yoshimura
authors.forename: M
authors.initials: M
authors.lastname: Yashiki
authors.forename: Y
authors.initials: Y
authors.lastname: Higashi
authors.forename: N
authors.initials: N
authors.lastname: Ishioka
authors.forename: Y
authors.initials: Y
authors.lastname: Nakano
authors.forename: R
authors.initials: R
authors.lastname: Kojima
authors.forename: M
authors.initials: M
authors.lastname: Kambe
authors.forename: G
authors.initials: G
authors.lastname: Kajiyama
mesh_terms: 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
chemical_list: 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