The cardioprotective effect of ischemic preconditioning (IPC) and ischemic postconditioning (IPoC) in adult hearts is mediated by nitric oxide (NO). During the early developmental period, rat hearts exhibit higher resistance to ischemia-reperfusion (I/R) injury, contain higher levels of serum nitrates, and their resistance cannot be further increased by IPC or IPoC. NOS blocker (L-NAME) lowers their high resistance. Wistar rat hearts (postnatal Days 1 and 10) were perfused according to Langendorff and exposed to 40 min of global ischemia followed by reperfusion with or without IPoC. NO and reactive oxygen species donors (DEA-NONO, SIN-1) and L-NAME were administered. Tolerance to ischemia decreased between Days 1 and 10. DEA-NONO (low concentrations) significantly increased tolerance to I/R injury on both Days 1 and 10. SIN-1 increased tolerance to I/R injury on Day 10, but not on Day 1. L-NAME significantly reduced resistance to I/R injury on Day 1, but actually increased resistance to I/R injury on Day 10. Cardioprotection by IPoC on Day 10 was not affected by either NO donors or L-NAME. It can be concluded that resistance of the neonatal heart to I/R injury is NO dependent, but unlike in adult hearts, cardioprotective interventions, such as IPoC, are most likely NO independent.

• Keywords
• DEA‐NONO, L‐NAME, SIN‐1, ischemic postconditioning, neonatal hearts, nitric oxide,
• MeSH
• Nitric Oxide Donors pharmacology   MeSH
• Ischemic Preconditioning, Myocardial methods   MeSH
• Ischemic Postconditioning * methods   MeSH
• Rats MeSH
• Molsidomine pharmacology   analogs & derivatives   MeSH
• Myocardium metabolism   MeSH
• NG-Nitroarginine Methyl Ester * pharmacology   MeSH
• Animals, Newborn * MeSH
• Nitric Oxide * metabolism   MeSH
• Rats, Wistar * MeSH
• Myocardial Reperfusion Injury * prevention & control   metabolism   MeSH
• Heart drug effects   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Nitric Oxide Donors MeSH
• Molsidomine MeSH
• NG-Nitroarginine Methyl Ester * MeSH
• Nitric Oxide * MeSH

In 2023, six decades have elapsed since the first experimental work on the heart muscle was published, in which a member of the Institute of Physiology of the Czech Academy of Sciences participated as an author; Professor Otakar Poupa was the founder and protagonist of this research domain. Sixty years - more than half of the century - is certainly significant enough anniversary that is worth looking back and reflecting on what was achieved during sometimes very complicated periods of life. It represents the history of an entire generation of experimental cardiologists; it is possible to learn from its successes and mistakes. The objective of this review is to succinctly illuminate the scientific trajectory of an experimental cardiological department over a 60-year span, from its inaugural publication to the present. The old truth - historia magistra vitae - is still valid. Keywords: Heart, Adaptation, Development, Hypoxia, Protection.

• MeSH
• Academies and Institutes * history   MeSH
• Biomedical Research * history   trends   MeSH
• History, 20th Century MeSH
• History, 21st Century MeSH
• Physiology history   MeSH
• Cardiology history   trends   MeSH
• Humans MeSH
• Heart physiology   MeSH
• Animals MeSH
• Check Tag
• History, 20th Century MeSH
• History, 21st Century MeSH
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Historical Article MeSH
• Review MeSH
• Geographicals
• Czech Republic MeSH

The heart is capable of extensive adaptive growth in response to the demands of the body. When the heart is confronted with an increased workload over a prolonged period, it tends to cope with the situation by increasing its muscle mass. The adaptive growth response of the cardiac muscle changes significantly during phylogenetic and ontogenetic development. Cold-blooded animals maintain the ability for cardiomyocyte proliferation even in adults. On the other hand, the extent of proliferation during ontogenetic development in warm-blooded species shows significant temporal limitations: whereas fetal and neonatal cardiac myocytes express proliferative potential (hyperplasia), after birth proliferation declines and the heart grows almost exclusively by hypertrophy. It is, therefore, understandable that the regulation of the cardiac growth response to the increased workload also differs significantly during development. The pressure overload (aortic constriction) induced in animals before the switch from hyperplastic to hypertrophic growth leads to a specific type of left ventricular hypertrophy which, in contrast with the same stimulus applied in adulthood, is characterized by hyperplasia of cardiomyocytes, capillary angiogenesis and biogenesis of collagenous structures, proportional to the growth of myocytes. These studies suggest that timing may be of crucial importance in neonatal cardiac interventions in humans: early definitive repairs of selected congenital heart disease may be more beneficial for the long-term results of surgical treatment.

• Keywords
• adaptation to overload, adaptive growth response, cardiac development, hyperplasia, hypertrophy, phylogeny, postnatal ontogeny,
• Publication type
• Journal Article MeSH
• Review MeSH

Cardioprotective effect of ischemic preconditioning (IPC) and ischemic postconditioning (IPoC) in adult hearts is mediated by mitochondrial-K-ATP channels and nitric oxide (NO). During early developmental period, rat hearts exhibit higher resistance to ischemia-reperfusion (I/R) injury and their resistance cannot be further increased by IPC or IPoC. Therefore, we have speculated, whether mechanisms responsible for high resistance of neonatal heart may be similar to those of IPC and IPoC. To test this hypothesis, rat hearts isolated on days 1, 4, 7, and 10 of postnatal life were perfused according to Langendorff. Developed force (DF) of contraction was measured. Hearts were exposed to 40 min of global ischemia followed by reperfusion up to the maximum recovery of DF. IPoC was induced by 5 cycles of 10-s ischemia. Mito-K-ATP blocker (5-HD) was administered 5 min before ischemia and during first 20 min of reperfusion. Another group of hearts was isolated for biochemical analysis of 3-nitrotyrosine, and serum samples were taken to measure nitrate levels. Tolerance to ischemia did not change from day 1 to day 4 but decreased on days 7 and 10. 5-HD had no effect either on neonatal resistance to I/R injury or on cardioprotective effect of IPoC on day 10. Significant difference was found in serum nitrate levels between days 1 and 10 but not in tissue 3-nitrotyrosine content. It can be concluded that while there appears to be significant difference of NO production, mito-K-ATP and ROS probably do not play role in the high neonatal resistance to I/R injury.

• Keywords
• 3-Nitrotyrosine, Ischemic postconditioning, Mito-K-ATP channel, Neonatal rats, Nitrates, Tolerance to ischemia,
• MeSH
• Potassium Channels metabolism   MeSH
• Ischemic Postconditioning * MeSH
• Rats MeSH
• Animals, Newborn MeSH
• Nitric Oxide metabolism   MeSH
• Rats, Wistar MeSH
• Myocardial Reperfusion Injury metabolism   physiopathology   prevention & control   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Potassium Channels MeSH
• mitochondrial K(ATP) channel MeSH Browser
• Nitric Oxide MeSH

Postnatal maturation of the heart is characterized by decreasing tolerance to ischemia/reperfusion (I/R) injury associated with significant changes in mitochondrial function. The aim of this study is to test the hypothesis that the role of the mitochondrial membrane permeability transition pore (MPTP) in the I/R injury differs in the neonatal and in the adult heart. For this purpose, the effect of blockade of MPTP on the degree of I/R injury and the sensitivity of MPTP to swelling-inducing agents was compared in hearts from neonatal (7 days old) and adult (90 days old) Wistar rats. It was found that the release of NAD(+) from the perfused heart induced by I/R can be prevented by sanglifehrin A (SfA) only in the adult myocardium; SfA had no protective effect in the neonatal heart. Furthermore, the extent of Ca-induced swelling of mitochondria from neonatal rats was significantly lower than that from the adult animals; mitochondria from neonatal rats were more resistant at higher concentrations of calcium. In addition, not only the extent but also the rate of calcium-induced swelling was about twice higher in adult than in neonatal mitochondria. The results support the idea that lower sensitivity of the neonatal MPTP to opening may be involved in the mechanism of the higher tolerance of the neonatal heart to I/R injury.

• MeSH
• Rats MeSH
• Lactones pharmacology   MeSH
• Animals, Newborn MeSH
• Rats, Wistar MeSH
• Mitochondrial Permeability Transition Pore MeSH
• Reperfusion Injury metabolism   MeSH
• Spiro Compounds pharmacology   MeSH
• Mitochondria, Heart metabolism   MeSH
• Mitochondrial Membrane Transport Proteins metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Lactones MeSH
• Mitochondrial Permeability Transition Pore MeSH
• sanglifehrin A MeSH Browser
• Spiro Compounds MeSH
• Mitochondrial Membrane Transport Proteins MeSH

The aim of the study was to find out whether administration of selenium (Se) will protect the immature heart against ischemia/reperfusion.The control pregnant rats were fed laboratory diet (0.237 mg Se/kg diet); experimental rats received 2 ppm Na(2)SeO(3) in the drinking water from the first day of pregnancy until day 10 post partum. The concentration of Se in the serum and heart tissue was determined by activation analysis, the serum concentration of NO by chemiluminescence, cardiac concentration of lipofuscin-like pigment by fluorescence analysis. The 10 day-old hearts were perfused (Langendorff); recovery of developed force (DF) was measured after 40 min of global ischemia. In acute experiments, 10 day-old hearts were perfused with selenium (75 nmol/l) before or after global ischemia. Sensitivity to isoproterenol (ISO, pD(50)) was assessed as a response of DF to increasing cumulative dose.Se supplementation elevated serum concentration of Se by 16%. Se increased ischemic tolerance (recovery of DF, 32.28 +/- 2.37 vs. 41.82 +/- 2.91%, P < 0.05). Similar results were obtained after acute administration of Se during post-ischemic reperfusion (32.28 +/- 2.37 vs. 49.73 +/- 4.40%, P < 0.01). The pre-ischemic treatment, however, attenuated the recovery (23.08 +/- 3.04 vs. 32.28 +/- 2.37%, P < 0.05). Moreover, Se supplementation increased the sensitivity to the inotropic effect of ISO, decreased cardiac concentration of lipofuscin-like pigment and serum concentration of NO. Our results suggest that Se protects the immature heart against ischemia/reperfusion injury. It seems therefore, that ROS may affect the function of the neonatal heart, similarly as in adults.

• MeSH
• Time Factors MeSH
• Myocardial Ischemia drug therapy   prevention & control   MeSH
• Myocardial Contraction drug effects   MeSH
• Rats MeSH
• Lipofuscin metabolism   MeSH
• Nitric Oxide blood   MeSH
• Perfusion MeSH
• Rats, Wistar MeSH
• Dietary Supplements MeSH
• Myocardial Reperfusion Injury drug therapy   prevention & control   MeSH
• Selenium blood   pharmacology   therapeutic use   MeSH
• Heart drug effects   MeSH
• Pregnancy MeSH
• Body Weight drug effects   MeSH
• Organ Size drug effects   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Lipofuscin MeSH
• Nitric Oxide MeSH
• Selenium MeSH

The aim of the study was to find out whether the changes in nutritional status induced by different litter size during early postnatal development can influence quantitative and qualitative protein remodeling and contractile performance of the myocardium. Male Wistar rats born at the same day were pooled together at 2 days postbirth and assigned by random selection to dams in groups of 4, 8 or 16 rats/litter. The animals were investigated at the age of 4 and 16 weeks. The results revealed that the early postnatal nutritional modification altered weight parameters: whereas lower heart weight persisted in slow-growing rats until 16 weeks, higher body weight of fast-growing rats returned to the control level at the age of 16 weeks. Altered nutritional status influenced also protein remodeling of the myocardium: the concentration of all noncollagenous proteins (fractions of metabolic and contractile proteins) significantly increased in slow-growing rats, on the other hand, the concentration of collagenous proteins (pepsin-soluble and -insoluble fractions) was higher in fast-growing animals. The changes were, however, only transitional: three months after the end of the weaning period most protein changes returned to the control level. However, higher concentration of total blood lipids and triglycerides in fast-growing rats persisted until adulthood. Nutritional changes had, however, only minor effect on ventricular performance. No differences among groups were observed in basal values of the left ventricular pressure, while the maximum pressure attained after an acute ventricular loading and the contractile reserve were significantly decreased in slow-growing 4 week old rats. The functional consequence of altered nutritional status during weaning was only transitional, in agreement with the transient character of most structural and biochemical markers of myocardial remodeling.

• MeSH
• Ventricular Function, Left MeSH
• Heart Function Tests MeSH
• Animal Nutritional Physiological Phenomena MeSH
• Animals, Suckling MeSH
• Myocardial Contraction MeSH
• Blood Glucose metabolism   MeSH
• Rats MeSH
• Myocardium metabolism   MeSH
• Nutritional Status * MeSH
• Weaning * MeSH
• Rats, Wistar MeSH
• Proteins metabolism   MeSH
• Heart physiology   MeSH
• Body Weight MeSH
• Organ Size MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Blood Glucose MeSH
• Proteins MeSH