title: Potassium-39 nuclear magnetic resonance observation of intracellular potassium without chemical shift reagents during metabolic inhibition in the isolated perfused rat heart.
abstract: The intracellular potassium content of perfused rat heart was measured by potassium-39 nuclear magnetic resonance (NMR) spectroscopy at 33 degrees C with an inversion recovery technique based on the fact that the spin-lattice relaxation time (T1) of the intracellular potassium (8.3 msec at 8.45 T) is much faster than that of the extracellular potassium (68 msec). Intracellular potassium decreased to 60.2 +/- 4.3% of the control level (mean +/- SEM, n = 6) at 40 minutes from the start of metabolic inhibition (2 mM cyanide, 0 mM glucose). Removal of cyanide restored intracellular potassium to 94.2 +/- 3.9% at 30 minutes from the restart of oxidative metabolism. The cumulative potassium loss was determined from the flow rate and potassium concentration of the coronary effluent, which reached 139 +/- 12 mumol/g dry wt during 40 minutes of metabolic inhibition. This value was calculated as 41.8% of intracellular potassium in the control heart and agreed with the decrement of intracellular potassium measured by NMR. During the metabolic inhibition and recovery period, a linear correlation was observed between the changes in 39K NMR-observed intracellular potassium and the cumulative potassium loss. The present results evaluate the inversion recovery technique as a method to successfully monitor the myocardial intracellular potassium.
authors.affiliation: Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kuki
authors.forename: E
authors.initials: E
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Watari
authors.forename: H
authors.initials: H
authors.lastname: Takami
authors.forename: H
authors.initials: H
authors.lastname: Matsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Kawashima
mesh_terms: D000818:Animals; D004419:Dysprosium; D004492:Edetic Acid / Q000031:analogs & derivatives; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007202:Indicators and Reagents; D004419:Dysprosium; C026059:triethylenetetraminehexaacetic acid; D004492:Edetic Acid; D011188:Potassium