Transmural saturation transfer analysis of the creatine kinase system in the mammalian heart

✍ Scribed by P.-M. L. Obitaille; A. Abduljalil; D. Rath; H. Zhang; R. L. Hamlin

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 604 KB
• Volume: 30
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910300103

✦ Synopsis

Abstract

^31^P NMR spatial localization and saturation transfer techniques were combined to enable the transmural measurement of the forward creatine kinase (CK) rate (ATP:creatine N‐phos‐photransferase, EC 2.7.3.2.) in the in vivo canine myocardium. Five epicardial towards endocardial regions of the left ventricle (LV) were simultaneously examined using spatially localized voxels. Although intralefl ventricular CP/ATP ratios were constant, the pseudo first order rate constant (K′) and the forward creatine kinase rate (R~t~) displayed a 61% variation across the LV wall. Because CK levels and calculated [ADP], [CP]and pH are transmurally invariant in the normal left ventricle, the observed changes in the R~t~ could not be explained by changes in the absolute levels of these substrates and of creatine kinase. In addition, because myocardial oxygen consumption rates are known to be higher in the endocardium, these results imply that forward creatine kinase rates are not directly related to oxidative phosphorylation rates.