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Cardiac output distribution in response to hypoxia in the chick embryo in the second half of the incubation time
Author(s) -
Mulder A. L. M.,
Golde J. C.,
Prinzen F. W.,
Blanco C. E.
Publication year - 1998
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1998.281br.x
Subject(s) - hypoxia (environmental) , incubation , cardiac output , biology , medicine , embryo , fetus , bradycardia , circulatory system , endocrinology , andrology , oxygen , heart rate , chemistry , blood pressure , pregnancy , biochemistry , genetics , organic chemistry , microbiology and biotechnology
1 The 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. 2 Fertilized 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. 3 Hypoxia 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). 4 The magnitude of the changes in cardiac output distribution to the heart, brain, liver and carcass in response to hypoxia increased with advancing incubation time. 5 The 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.