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 β-adrenergic signaling pathways and antioxidant defence mechanisms play important roles in maintaining proper heart function. Here, we examined the effect of chronic normobaric hypoxia (CNH, 10% O2, 3 weeks) on myocardial β-adrenergic signaling and selected components of the antioxidant system in spontaneously hypertensive rats (SHR) and in a conplastic SHR-mtBN strain characterized by the selective replacement of the mitochondrial genome of SHR with that of the more ischemia-resistant Brown Norway strain. Our investigations revealed some intriguing differences between the two strains at the level of β-adrenergic receptors (β-ARs), activity of adenylyl cyclase (AC) and monoamine oxidase A (MAO-A), as well as distinct changes after CNH exposure. The β2-AR/β1-AR ratio was significantly higher in SHR-mtBN than in SHR, apparently due to increased expression of β2-ARs. Adaptation to hypoxia elevated β2-ARs in SHR and decreased the total number of β-ARs in SHR-mtBN. In parallel, the ability of isoprenaline to stimulate AC activity was found to be higher in SHR-mtBN than that in SHR. Interestingly, the activity of MAO-A was notably lower in SHR-mtBN than in SHR, and it was markedly elevated in both strains after exposure to hypoxia. In addition to that, CNH markedly enhanced the expression of catalase and aldehyde dehydrogenase-2 in both strains, and decreased the expression of Cu/Zn superoxide dismutase in SHR. Adaptation to CNH intensified oxidative stress to a similar extent in both strains and elevated the IL-10/TNF-α ratio in SHR-mtBN only. These data indicate that alterations in the mitochondrial genome can result in peculiar changes in myocardial β-adrenergic signaling, MAO-A activity and antioxidant defence and may, thus, affect the adaptive responses to hypoxia.

• Keywords
• Adenylyl cyclase, Antioxidant defence, Chronic hypoxia, Mitochondrial genome, Monoamine oxidase A, Myocardium, SHR, β-adrenergic receptors,
• MeSH
• Adenylyl Cyclases metabolism   MeSH
• Receptors, Adrenergic, beta metabolism   MeSH
• Hypoxia metabolism   MeSH
• Rats MeSH
• Malondialdehyde metabolism   MeSH
• Monoamine Oxidase metabolism   MeSH
• Myocardium metabolism   MeSH
• Rats, Inbred SHR MeSH
• Signal Transduction physiology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Adenylyl Cyclases MeSH
• Receptors, Adrenergic, beta MeSH
• Malondialdehyde MeSH
• Monoamine Oxidase MeSH

Adaptation to chronic hypoxia represents a potential cardioprotective intervention reducing the extent of acute ischemia/reperfusion (I/R) injury, which is a major cause of death worldwide. The main objective of this study was to investigate the anti-apoptotic Akt/hexokinase 2 (HK2) pathway in hypoxic hearts subjected to I/R insult. Hearts isolated from male Wistar rats exposed either to continuous normobaric hypoxia (CNH; 10% O2) or to room air for 3 weeks were perfused according to Langendorff and subjected to 10 min of no-flow ischemia and 10 min of reperfusion. The hearts were collected either after ischemia or after reperfusion and used for protein analyses and quantitative fluorescence microscopy. The CNH resulted in increased levels of HK1 and HK2 proteins and the total HK activity after ischemia compared to corresponding normoxic group. Similarly, CNH hearts exhibited increased ischemic level of Akt protein phosphorylated on Ser473. The CNH also strengthened the interaction of HK2 with mitochondria and prevented downregulation of mitochondrial creatine kinase after reperfusion. The Bax/Bcl-2 ratio was significantly lower after I/R in CNH hearts than in normoxic ones, suggesting a lower probability of apoptosis. In conclusion, the Akt/HK2 pathway is likely to play a role in the development of a cardioprotective phenotype of CNH by preventing the detachment of HK2 from mitochondria at reperfusion period and decreases the Bax/Bcl-2 ratio during I/R insult, thereby lowering the probability of apoptosis activation in the mitochondrial compartment.

• Keywords
• Heart, Hexokinase, Hypoxia, Ischemia/reperfusion, Mitochondria, Protein kinase B/Akt,
• MeSH
• Hexokinase metabolism   MeSH
• Rats MeSH
• Myocardium enzymology   pathology   MeSH
• Rats, Wistar MeSH
• Proto-Oncogene Proteins c-akt metabolism   MeSH
• Myocardial Reperfusion Injury enzymology   pathology   MeSH
• Mitochondria, Heart enzymology   pathology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Hexokinase MeSH
• Proto-Oncogene Proteins c-akt MeSH