[Dynamics of the cAMP and cGMP content of the heart in transient coronary insufficiency in rats].

Experiments made on 127 white random-bred male rats weighing 200 +/- 10 g with transitory coronary insufficiency (TCI) with varying duration of myocardial ischemia (MI) have revealed consistent changes in the heart cAMP and cGMP. During MI, there was a biphasic variation in the concentration of cyclic nucleotides: an initial appreciable increase in the concentration was replaced by its lowering. At the same time the time course of cGMP content was more mobile in nature as compared to cAMP Reperfusion made at an early period (within the first 40 min) did not normally bring about the normalization of heart content of cyclic nucleotides whose concentration time course depended on the duration of the preceding MI. The pattern of changes in the concentration of cyclic nucleotides in the heart in TCI correlated to a significant degree with the previously described time course of the activity of the sympath- and cholinergic mechanisms by which heart work, contractile function and rhythm are controlled during TCI.