The role of age-related factors in the effect of long-term perfusion on the contractility of isolated heart

Experiments on isolated hearts of mature and senescent rats showed that in mature rats the heart contractility decreased to a greater extent during the initial hours of a long-term perfusion, but in mature heart tolerance to perfusion was higher. Creatine phosphokinase activity drastically increased in the perfusate of senescent hearts and changed insignificantly in the perfusate of mature hearts. In mature rats a long-term perfusion was accompanied by activation of Na,K-ATPase, which was prevented by actinomycin D. Transfer of perfusate in the donor-recipient double-heart experiments with prior administration of actinomycin D showed that long-term perfusion induces the synthesis of a regulator factor (inverter) in the heart of mature rats which modulates myocardial contractility. This regulator peptide contributes to adaptive potency of the heart in mature animals. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 7, pp. 505–509, November, 1998