Determination of intracellular calcium in vivo via fluorine-19 nuclear magnetic resonance spectroscopy
Song, S.K.; Hotchkiss, R.S.; Neil, J.; Morris, P.E.; Hsu, C.Y.; Ackerman, J.J.
American Journal of Physiology 269(2 Pt 1): C318-C322
1995
ISSN/ISBN: 0002-9513 PMID: 7653513 Document Number: 443635
Fluorine-19-nuclear magnetic resonance (19F-NMR) spectroscopic detection of the NMR-active Ca-2+ indicator 5-fluoro-1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (5F-BAPTA) is one method for measuring cytosolic free Ca-2+ concentration ((Ca-2+)-i) and has been used previously to measure (Ca-2+), in isolated cells and perfused organs. The aim of the present investigation was to demonstrate the feasibility of determining (Ca-2+), in vivo and in situ using 19F-NMR and 5F-BAPTA. Experiments were performed on male Sprague-Dawley rats with a surface-coil antenna employed for NMR interrogation. The Ca-2+ indicator, 5F-BAPTA, was infused either intravenously (kidney, spleen) or intraventricularly (brain) as a 100 mg/ml solution of the cell-permeant acetoxymethyl ester (5F-BAPTA-AM) in dimethyl sulfoxide. Rats tolerated intravenous infusion without evident change in mean arterial blood pressure. In all tissues examined, kidney, spleen, and brain, (Ca-2+), was apprx 200 nM. To our knowledge, these results represent the first in vivo and in situ determinations of (Ca-2+)-i employing 19F-NMR.