Determination of intracellular calcium in vivo via fluorine-19 nuclear magnetic resonance spectroscopy.
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.
Song
S K
SK
Department of Chemistry, Washington University, St. Louis 63130-4899, USA.
Hotchkiss
R S
RS
Neil
J
J
Morris
P E
PE
Hsu
C Y
CY
Ackerman
J J
JJ
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004533:Egtazic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives; D005240:Feasibility Studies; D005461:Fluorine; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D007425:Intracellular Membranes / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
D005461:Fluorine; D004533:Egtazic Acid; C039877:5,5'-difluoro-1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium