Premium
Effects of ischemia on intracellular rubidium in pig and rat hearts: 87 Rb NMR imaging and spectroscopic study
Author(s) -
Kupriyanov V.V.,
Xiang B.,
Sun J.,
Jilkina O.,
Dai G.,
Deslauriers R.
Publication year - 2000
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/1522-2594(200008)44:2<193::aid-mrm5>3.0.co;2-x
Subject(s) - ischemia , perfusion , rubidium , chemistry , nuclear magnetic resonance , anterior wall , anatomy , nuclear medicine , medicine , potassium , physics , organic chemistry
87 Rb MR imaging and spectroscopy were used to study the effects of ischemia on the properties of K + in cardiac tissue. Isolated pig and rat hearts perfused by the Langendorff method with Krebs‐Henseleit buffer were preloaded with Rb + . Ischemia ( Isc ) was induced by 120‐min occlusion of the left anterior descending artery in the pig hearts or by stopping perfusion for 33 min in the rat hearts. Serial 87 Rb MR images or spectra from the anterior ( An ) LV wall of pig hearts were acquired continuously. The intensities of the Rb images of the An and posterior ( Pos ) walls were similar and stable during the first 45 min of ischemia. The intensity of signal from the An wall ( Isc ) then gradually increased by 60 ± 8% relative to the preischemic value (vs. 31 ± 5% increase in Pos wall) and necrosis (19 ± 5% of the LV wall mass) developed upon reperfusion. The Rb + content was lower in the ischemic ( An ) than in the normal ( Pos ) area (22.3 ± 3 vs. 28.4 ± 1.3 mmol/g wet wt). A similar pattern was observed in the peak heights of 87 Rb spectra from the An wall, which increased by 40 ± 16% (vs. 21 ± 11% in control) due to a 12% decrease in the apparent Rb linewidth (LW) and a 24 ± 14% increase in the peak area. The Rb peak comprised narrow (297 ± 21 Hz) and broad (1098 ± 40 Hz, 59 ± 3% of total area) Lorentzian components. The LW of the broad component decreased by 14%, while the narrow component did not change markedly. In the rat hearts ischemia caused a 33 ± 4% increase in the 87 Rb peak height as a result of peak narrowing (13 ± 1%), and an increase in peak area (17 ± 5%). The decreases in LW and increases in Rb + visibility can be explained by an increase in Rb + mobility caused by displacement of Rb + from anionic binding sites by H + (ischemic acidosis) and changes in intracellular compartmentalization of Rb + . Magn Reson Med 44:193–200, 2000. © 2000 Wiley‐Liss, Inc.