The adaption to environmental factors: hazard or programme.
Any living structure, from cell to the entire organism, can adapt to internal or external factors only by triggering pre-existing mechanisms. All these mechanisms have a morphological support programmed within foetal inactive genes or adult genes with low activity. These genes are activated by a chain of reactions that usually starts with perceiving the stimulus at the membrane level and finishes with the synthesis of some proteins (enzymes, membrane receptors, etc.). The adaptative changes of the enzymatic and structural register would be impossible without the activation of genes other than those operating in normal condition. It is obvious that the same pre-existing genetic mechanism also functions in myocardial hypertrophy or neoangiogenesis. Actually, "a genetic orchestra" is ready to perform at a given moment the new tone suggested by the ever changing condition under which the myocardial fiber acts. However, the concept of programmed adaption has not only a theoretical value; in medical practice, the prediction, prevention and treatment of ischemic heart disease will benefit from the theoretic support of understanding the cardiac adaptative behaviour. It is obvious that this adaptation programmes cannot always save the heart from necrosis and the subject from death due to fatal arrhythmias or cardiogenic shock.
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Nicolae C. Paulescu Departament of Physiology, University of Medicine and Pharmacy Carol Davila, Bucharest.
D000222:Adaptation, Physiological / Q000502:physiology*; D004777:Environment; D006801:Humans; D019194:Ischemic Preconditioning; D017202:Myocardial Ischemia / Q000503:physiopathology*