EARLY CHANGES IN PROTEIN-SYNTHESIS IN EPICARDIAL CORONARY-ARTERY OF PRESSURE-OVERLOADED HEART

In anesthetized dogs, a 4-h, similar to 30% increase in blood pressure induced by constriction of the abdominal aorta brought about an incre ase in the total RNA content in the left anterior descending coronary artery (LADCA) and the left ventricular (LV) myocardium(9.05 +/- 1.72 and 11.06 +/- 4.68%, respectively) but not in the left circumflex coro nary artery (LCCA). Under the same experimental conditions, [C-14]leuc ine incorporation increased in LADCA and LV myocardium (45.34 +/- 13.5 4 and 58.07 +/- 11.91%, respectively), but not in LCCA. The data indic ate an early shift in protein synthesis in LADCA and simultaneously in the myocardium during a short-term presser event. The difference in t he shift of protein synthesis in the two main branches of the left cor onary artery was related to the quantitatively different deformation o f the LADCA and LCCA due to different deformation of the underlying my ocardium and/or of the annulus fibrosus atrioventricularis during chan ges in the left or right ventricle volume [M. Gerova, E. Barta, M. Sto larik, and J. Gero. Am. J. Physiol. 262 (Heart Circ. Physiol. 31): H10 49-H1053, 1992]. The results support the hypothesis that the deformati on and/or rate of deformation of cells in the coronary wall may trigge r an increase in protein synthesis. Changes in protein synthesis in th e myocardium and LADCA were found to be reversible 2 h after releasing the aortic constriction.