[Elimination of impairment of myocardial relaxation and contraction during stress with uridine, a cofactor of glycogen resynthesis].

The effects of administering high glucose concentration (22 mM) or uridine, a cofactor of glycogen synthesis (2 X 10(-4) M), into the perfusion medium on the post-stress disturbances of the rat isolated atrium extensibility and contractile function were studied. Stress decreased the extensibility of the atrial myocardium and caused the depression of the developing systolic pressure in the isometric regime of contraction. These disturbances could be completely eliminated by a 4-fold increase of glucose concentration compared with physiological concentration, namely from 5.5 to 22 mM. The same radical effect was attained under unchanged glucose concentration by addition of uridine (2 X 10(-4) M) into the solution. The data evidence that the disturbances in glycogen resynthesis and glycolysis play an important role in the occurrence of post-stress disturbances of heart contractile function and hold promise for uridine use with a view of elimination of the stress-induced and ischemic heart injuries.