Producción CyT
Congreso
Autoría
Fecha
2017
Editorial y Lugar de Edición
Fundacion Medicina
Resumen
Información suministrada por el agente en
SIGEVA
Staircase phenomenon establishes the relationship between heart rate (HR) and contractile force: an increase in heart rate, progressively increases the force of contraction. This physiological response is important during exercise and it is observed in healthy individuals and big mammals. Instead, negative staircase occurs in human heart failure, small mammals and other vertebrates. Drosophila melanogaster is a genetic useful model for cardiac studies. However, its physiology is less known and ...
Staircase phenomenon establishes the relationship between heart rate (HR) and contractile force: an increase in heart rate, progressively increases the force of contraction. This physiological response is important during exercise and it is observed in healthy individuals and big mammals. Instead, negative staircase occurs in human heart failure, small mammals and other vertebrates. Drosophila melanogaster is a genetic useful model for cardiac studies. However, its physiology is less known and it is essential characterize it to extrapolate results of mutagenesis of human conserved genes. In order to determine the nature of the staircase phenomenon in D. melanogaster we measured mechanical activity and Ca2+ transient of adult flies exposed to increments of frequency of 0.5 Hz over the basal spontaneous heart rate. Average results of movement recording show not relative changes of mechanical activity at three augmented frequencies (basal: 100% n= 9, F1: 103.77 ± 8.03 n=9, F2: 95.26 ± 9.5 n= 7, F3 105.67 ± 23.9 n=4) while Ca2+ transient exhibit a negative staircase (basal: 100% n= 5, F1: 73.04 ± 6.4 n=4, F2: 62.17 ± 7.41 n= 5, F3 42.68 ± 8.63 n=5) as its indicated by correlation coefficient of Pearson R2 = 0.89. As occur in other species, we observed a tendency of acceleration of relaxation in D. melanogaster. The fruit fly contains homologous proteins responsible of Ca2+ handling and force generation hence molecular mechanisms that regulate the staircase phenomenon in humans could be explored in this genetic model.
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Palabras Clave
HeartStaircasedrosophila