Age dependence of spontaneous frequencies and intracardial Baindridge-effect of rabbits between the 3rd and 18th day of life
Cermak, M.; Rossberg, F.
Biomedica Biochimica Acta 47(2): 149-152
1988
ISSN/ISBN: 0232-766X PMID: 3178780 Document Number: 319396
With continuous perfusion at defined intraluminal pressures isolated right atria from rabbits were examined. Age groups of 3-6, 9-12 and 15-18 days of life were used to measure the chronotropic response to change of atrial pressure over a range of 0.1 to 0.9 kPa (10-90 mm H2O). At transmural pressure of 0.1 kPa (control) the rate of spontaneously beating atria decreased progressively with age over the first three weeks. As compared to the group of 15-18 days, for each intraluminal pressure the atrial rate was significantly higher in the group of 3-6 days. Already 3-6 days after birth the chronotropic self-control mediated by stretch (Bainbridge effect) was present, this response did not vary significantly from that obtained in the group of 15-18 days of life.