Abstract
In phase I of this study, the rate of protein synthesis was measured by the incorporation of [3H]leucine into the protein pool in the heart of conscious rabbits. At 2 h after ischemic preconditioning (PC) with six 4-min occlusion/4-min reperfusion (O/R) cycles (group II), the [3H]leucine content in the ischemic-reperfused region was increased by 82% compared with that in controls (group I), indicating increased protein synthesis. This increase was completely abrogated by pretreatment with cycloheximide (CH; group III). In phase II, rabbits underwent six O/R cycles for three consecutive days (days 1-3). Controls (group IV) exhibited late PC against myocardial stunning on days 2 and 3. In group V, which received CH 30 min before the 1st O/R cycle on day 1 (same dose as group III), late PC against stunning on day 2 was completely abrogated. In group VI, pretreatment with CH 24 h before the 1st sequence of O/R cycles had no effect on myocardial stunning on day 1, indicating that the absence of late PC on day 2 in group V cannot be ascribed to delayed toxicity of CH. Taken together, these results demonstrate that, in the conscious rabbit, ischemic PC causes a rapid increase in myocardial protein synthesis and that this increased protein synthesis (or at least a fraction of it) is necessary for the development of the protection against myocardial stunning 24 h later. The late phase of ischemic PC is therefore dependent on the formation of new proteins in intact animals.
Original language | English (US) |
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Pages (from-to) | H874-H884 |
Journal | American Journal of Physiology - Heart and Circulatory Physiology |
Volume | 277 |
Issue number | 3 46-3 |
DOIs | |
State | Published - Sep 1999 |
Keywords
- Cycloheximide
- Myocardial ischemia
- Myocardial reperfusion
- Systolic wall thickening
- [H]leucine
ASJC Scopus subject areas
- Physiology
- Cardiology and Cardiovascular Medicine
- Physiology (medical)