title: Hypermagnesemia does not increase brain intracellular magnesium in newborn swine.
abstract: Phosphorus-31 magnetic resonance spectroscopy was used in 2-day (n = 4) and 40-day (n = 4) miniswine to determine whether plasma hypermagnesemia alters brain intracellular magnesium concentration and if the plasma-brain intracellular magnesium relationship changes with age. At control, brain intracellular magnesium concentration was similar in the 2-day (0.24 +/- 0.04 mM) and 40-day groups (0.21 +/- 0.01 mM). Intravenous infusions of magnesium sulfate (MgSO(4), 60 minute) raised plasma magnesium concentration to 4-6 mM in both groups. During and for 3 hours after MgSO(4) infusions, there were no changes in brain intracellular magnesium concentration in either group and no correlation between plasma and brain intracellular magnesium (r = 0.11 and 0.08 for 2- and 40-day groups, respectively). Brain intracellular magnesium concentration appears to be tightly regulated.
authors.affiliation: Texas Women's Hospital, Houston, Texas, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Gee
authors.forename: R J
authors.initials: RJ
authors.lastname: Corbett
authors.forename: J M
authors.initials: JM
authors.lastname: Perlman
authors.forename: A R
authors.initials: AR
authors.lastname: Laptook
mesh_terms: D000367:Age Factors; D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects*; D007262:Infusions, Intravenous; D008274:Magnesium / Q000097:blood / Q000493:pharmacokinetics*; D008278:Magnesium Sulfate / Q000008:administration & dosage*; D009682:Magnetic Resonance Spectroscopy; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D013552:Swine
chemical_list: D018696:Neuroprotective Agents; D008278:Magnesium Sulfate; D008274:Magnesium