TY - JOUR
T1 - In vivo alterations of high-energy phosphates and intracellular pH during reversible ischemia in pigs
T2 - A 31P magnetic resonance spectroscopy study
AU - Camacho, S. Albert
AU - Lanzer, Peter
AU - Toy, Beau J.
AU - Gober, Joel
AU - Valenza, Mario
AU - Botvinick, Elias H.
AU - Weiner, Michael W.
N1 - Funding Information:
I-rom the Cardiovascular Research Institute, the Departments of Medicine iCardiology) and Radiology, University of California, and the Magnetic Resonance Unit, Veterans Administration Medical Center. Supported in part by American Heart Association, California Affiliate, grant-in-aid award 86-N103; by a grant from the Fannie E. Rippel Foundation, Madison, NJ; by NIH Institutional NRSA grant in Heart and Vascular Diseases HL 07192 (Dr. Camacho); part by Progetto Sanitaria Finalizzato Assessorato Sanim Regione Sicilia, N318/M, (Dr. Valenza); in part by a grant from the George Smith Fund, San Francisco, CA (Dr. Botvinick); by NIH grant ROl DK 33292-04 (Dr. Weiner); and by the Veterans Administration Medical Research Service. for publication March 7. 1988; accepted April 20, 1988. requests: S. Albert Carnacho, MD, Veterans Administration Center, Magnetic Resonance (IlD), 4150 Clement St., San CA 94121.
PY - 1988/9
Y1 - 1988/9
N2 - Phosphorus-31 magnetic resonance spectroscopy was used to study the relationship between metabolic and functional alterations during acute regional ischemia in vivo. Phosphocreatine, adenosine triphosphate (ATP), inorganic phosphate, and intracellular pH (pH) were monitored in 11 pigs at 2-minute intervals during 4 and 20 minutes of acute left anterior descending coronary artery occlusion followed by 20 minutes of reperfusion. In a parallel series of experiments, segment shortening was continuously monitored by sonomicrometry during the early ischemic period. Segment shortening decreased precipitously after coronary occlusion, and systolic expansion was noted within 30 seconds. Phosphocreatine levels decreased rapidly and reached a minimum value of 44 ± 13% (mean ± SE) of the control value by 20 minutes of ischemia. Ischemia-induced reduction of ATP was small and not statistically significant. Inorganic phosphate increased rapidly to a peak level of 158 ± 9% of the control value by 4 minutes of ischemia. Intracellular pH decreased 0.76 ± 0.04 units during the initial 10 minutes of ischemia and subsequently stabilized. After reperfusion, phosphocreatine, inorganic phosphate, and pHi recovery occurred within 4 minutes and was similar in the 4- and 20- minute ischemia groups. These results indicate that the changes in high-energy phosphates and pHi observed during both 4 and 20 minutes of coronary occiusion are rapidly reversible. The temporal course of metabolic and functional alterations during early ischemia suggests that if these are causally related the decline in contractility is mediated by an increase in inorganic phosphate, a decrease in pHi, or both rather than by loss of ATP.
AB - Phosphorus-31 magnetic resonance spectroscopy was used to study the relationship between metabolic and functional alterations during acute regional ischemia in vivo. Phosphocreatine, adenosine triphosphate (ATP), inorganic phosphate, and intracellular pH (pH) were monitored in 11 pigs at 2-minute intervals during 4 and 20 minutes of acute left anterior descending coronary artery occlusion followed by 20 minutes of reperfusion. In a parallel series of experiments, segment shortening was continuously monitored by sonomicrometry during the early ischemic period. Segment shortening decreased precipitously after coronary occlusion, and systolic expansion was noted within 30 seconds. Phosphocreatine levels decreased rapidly and reached a minimum value of 44 ± 13% (mean ± SE) of the control value by 20 minutes of ischemia. Ischemia-induced reduction of ATP was small and not statistically significant. Inorganic phosphate increased rapidly to a peak level of 158 ± 9% of the control value by 4 minutes of ischemia. Intracellular pH decreased 0.76 ± 0.04 units during the initial 10 minutes of ischemia and subsequently stabilized. After reperfusion, phosphocreatine, inorganic phosphate, and pHi recovery occurred within 4 minutes and was similar in the 4- and 20- minute ischemia groups. These results indicate that the changes in high-energy phosphates and pHi observed during both 4 and 20 minutes of coronary occiusion are rapidly reversible. The temporal course of metabolic and functional alterations during early ischemia suggests that if these are causally related the decline in contractility is mediated by an increase in inorganic phosphate, a decrease in pHi, or both rather than by loss of ATP.
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U2 - 10.1016/0002-8703(88)90327-4
DO - 10.1016/0002-8703(88)90327-4
M3 - Article
C2 - 3414485
AN - SCOPUS:0023676996
SN - 0002-8703
VL - 116
SP - 701
EP - 708
JO - American heart journal
JF - American heart journal
IS - 3
ER -