AJP - Cell Physiology, Vol 269, Issue 2 C318-C322, Copyright © 1995 by American Physiological Society
Determination of intracellular calcium in vivo via fluorine-19 nuclear magnetic resonance spectroscopy
S. K. Song, R. S. Hotchkiss, J. Neil, P. E. Morris Jr, C. Y. Hsu and J. J. Ackerman
Department of Chemistry, Washington University, St. Louis 63130-4899, USA.
Fluorine-19-nuclear magnetic resonance (19F-NMR) spectroscopic detection of
the NMR-active Ca2+ indicator
5-fluoro-1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
(5F-BAPTA) is one method for measuring cytosolic free Ca2+ concentration
([Ca2+]i) and has been used previously to measure [Ca2+]i in isolated cells
and perfused organs. The aim of the present investigation was to
demonstrate the feasibility of determining [Ca2+]i 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 Ca2+ 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, [Ca2+]i was approximately 200 nM. To our knowledge, these results
represent the first in vivo and in situ determinations of [Ca2+]i employing
19F-NMR.
