In vivo alterations of high-energy phosphates and intracellular pH during reversible ischemia in pigs: A 31P magnetic resonance spectroscopy study

S. Albert Camacho, Peter Lanzer, Beau J. Toy, Joel Gober, Mario Valenza, Elias H. Botvinick, Michael W. Weiner

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)701-708
Number of pages8
JournalAmerican heart journal
Volume116
Issue number3
DOIs
StatePublished - Sep 1988
Externally publishedYes

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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