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An ex-ovo Chicken Embryo Culture System Suitable for Imaging and Microsurgery Applications
Published on: October 23, 2010
Influence of acute alterations in cycle length on ventricular function in chick embryos
C B Casillas1, J P Tinney, B B Keller
1National Institutes of Health Specialized Center of Research in Pediatric Cardiovascular Diseases, Department of Pediatrics, University of Rochester School of Medicine and Dentistry, New York 14642.
The American Journal of Physiology
|September 1, 1994
Summary
Chick embryos maintain cardiac output by adjusting stroke volume (SV) when heart rate (HR) changes. Ventricular preload and cardiac function adapt to altered cycle lengths (CL) via unique embryonic cardiovascular dynamics.
Area of Science:
- Developmental Biology
- Cardiovascular Physiology
- Embryology
Background:
- Cardiac morphogenesis involves dramatic increases in heart rate (HR), developed pressure, and stroke volume (SV).
- The embryonic heart exhibits unique compensatory mechanisms to maintain cardiac output during acute changes in cycle length (CL).
Purpose of the Study:
- To quantify the relationship between CL, cardiac time intervals, ventricular preload, and ventricular function in stage 21 Leghorn chick embryos.
- To determine embryonic pressure-volume relations during alterations in CL.
Main Methods:
- Transiently altered CL in stage 21 Leghorn chick embryos using a preheated or cooled metal probe on the sinus venosus.
- Measured cardiac time intervals, stroke volume (SV), end-diastolic volume, and end-systolic pressure.
Main Results:
- Isometric relaxation, diastolic filling, and systolic ejection times varied linearly with CL; isometric contraction times remained similar.
- Stroke volume (SV) demonstrated a linear relationship with CL, ejection time, and end-diastolic volume.
- The relationship between SV and end-systolic pressure was inverse, contrasting with mature hearts. Embryonic ventricular preload was acutely influenced by diastolic filling time.
Conclusions:
- Chick embryo cardiac output is optimized during CL changes through ventricular-vascular interactions matching SV inversely to HR.
- Embryonic cardiovascular regulation differs significantly from mature heart physiology, particularly in pressure-volume relationships.
