Cardiac output distribution in response to hypoxia in the chick embryo in the second half of the incubation time
Article first published online: 22 SEP 2004
The Journal of Physiology
Volume 508, Issue 1, pages 281–287, April 1998
How to Cite
Mulder, A. L. M., van Golde, J. C., Prinzen, F. W. and Blanco, C. E. (1998), Cardiac output distribution in response to hypoxia in the chick embryo in the second half of the incubation time. The Journal of Physiology, 508: 281–287. doi: 10.1111/j.1469-7793.1998.281br.x
- Issue published online: 22 SEP 2004
- Article first published online: 22 SEP 2004
- (Received 12 June 1997; accepted after revision 16 December 1997)
- 1The fetus develops cardiovascular adaptations to protect vital organs in situations such as hypoxia and asphyxia. These include bradycardia, increased systemic blood pressure and redistribution of the cardiac output. The extent to which they involve maternal or placenta influences is not known. The objective of the present work was to study the cardiac output distribution in response to hypoxia in the chick embryo, which is independent of the mother.
- 2Fertilized eggs were studied at three incubation times (10-13 days, 14-16 days and 17-19 days of a normal incubation time of 21 days). Eggs were placed in a Plexiglass box in which the oxygen concentration could be changed. Eggs were opened at the air cell and a chorioallantoic vein was catheterized. Cardiac output distribution was measured with 15 μm fluorescent microspheres injected during normoxia, during the last minute of a 5 min period of hypoxia and after 5 min of subsequent reoxygenation.
- 3Hypoxia caused a redistribution of the cardiac output in favour of heart (+17 to +160 % of baseline) and brain (+21 to +57 % of baseline) at the expense of liver (-3 to -65 % of baseline), yolk-sac (-46 to -77 % of baseline) and carcass (-6 to -33 % of baseline).
- 4The magnitude of the changes in cardiac output distribution to the heart, brain, liver and carcass in response to hypoxia increased with advancing incubation time.
- 5The data demonstrate the development of a protective redistribution of the cardiac output in response to hypoxia in the chick embryo from day 10 of incubation.