Protective effect of carteolol, a beta-blocker, on myocardial cellular damage in ischemic and reperfused pig hearts: assessment with gated in vivo 31-phosphorus magnetic resonance spectroscopy and electron microscopy.
To assess the effect of carteolol, a beta-blocker, on ischemia and reperfusion, changes in the ultrastructure of myocytes and energy metabolism were studied by 31P-NMR in 41 pig hearts without collateral circulation. The left anterior descending coronary artery was occluded for 20 min and reperfused for 120 min in three groups: seven pigs (group 1, no treatment with carteolol; group 2, pre-ischemia treatment with carteolol (10 micrograms/kg); group 3, post-ischemia treatment with carteolol before reperfusion). Other groups of five pigs were killed after 120 min of ischemia (group 4, no treatment; group 5, pre-ischemia treatment) or 20 min of ischemia (group 6, no treatment; group 7, pre-ischemia treatment). After 20 min of ischemia, ATP was higher in groups 2 (76 +/- 9% of the baseline value) than in group 1 (59 +/- 5%) and group 3 (60 +/- 10%). However, the difference disappeared after 30 min of ischemia. After 120 min of reperfusion, ATP showed much better recovery in group 2 (92 +/- 9%) than in groups 1 (66 +/- 7%) and 3 (68 +/- 10%). Ischemic injury, as viewed by light and electron microscopy, was milder in group 7 than in group 6 after 20 min occlusion, but the myocytes were almost normal after 120 min reperfusion in groups 1 to 3. The heart rate, blood pressure and rate pressure product showed no significant difference among the groups. These results indicate that pre-ischemia treatment with carteolol provided protection against ischemic cellular injury and accelerated the repletion of ATP during reperfusion, but the post-ischemia treatment did not lead to recovery of ATP. Therefore, the favorable effect during reperfusion of pre-ischemia treatment with carteolol depends on its protective effect during ischemia.
Ishida
M
M
Department of Internal Medicine, Kyoto University, Japan.
Fujiwara
H
H
Kida
M
M
Kawai
C
C
Nakayama
S
S
Yamashita
S
S
Miura
I
I
Yabuuchi
Y
Y
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002354:Carteolol / Q000627:therapeutic use*; D003327:Coronary Disease / Q000473:pathology / Q000517:prevention & control*; D006439:Hemodynamics; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D013552:Swine
D010710:Phosphates; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D002354:Carteolol