Time course of the recovery of adenosine triphosphate content with adenosine in post-ischemic hearts--a 31P magnetic resonance spectroscopy study.
Restoration of the ATP level after brief ischemia is limited by slow de novo ATP synthesis and substrate loss in a salvage pathways for ATP synthesis, and complete recovery requires several days in the stunned heart. Adenosine is a substrate for myocardial ATP synthesis. We measured myocardial ATP in both ex vivo and in vivo experiments by 31P magnetic resonance spectroscopy (31P-MRS) and investigated the time course of ATP content recovery after application of adenosine. Guinea-pig perfused hearts were subjected to 30 min of global ischemia and reperfused for 3 h with 50 microM adenosine. The ATP level increased from 54 +/- 5% to 117 +/- 4% of the pre-ischemic value (p < 0.01). In dogs, we occluded the left anterior descending coronary artery for 40 min to produce regional ischemia. Afterwards, we administered 100 mumol/h adenosine into the left ventricle for 2 h. ATP levels increased from 63 +/- 4% to 77 +/- 5% of the pre-ischemic value with adenosine (p < 0.05). However, ATP levels did not increase for a few hours after reperfusion both ex vivo and in vivo. Our 31P-MRS studies demonstrated that brief ischemia depressed ATP levels and that administration of adenosine accelerated ATP formation in post-ischemic hearts.
First Department of Internal Medicine Osaka City University Medical School, Japan.
M
M
Yoshiyama
M
M
Ishikawa
I
I
Miura
K
K
Takeuchi
T
T
Takeda
D000241:Adenosine / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D000818:Animals; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism
D000255:Adenosine Triphosphate; D000241:Adenosine