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Volume expansion attenuates baroreflex sensitivity in the conscious nonhuman primate
K G Cornish1, M W Barazanji, T Yong
1Department of Physiology and Biophysics, University of Nebraska College of Medicine, Omaha 68105-1065.
The American Journal of Physiology
|September 1, 1989
Summary
Volume expansion (VE) in conscious monkeys significantly reduced the baroreflex control of heart rate. This study shows VE attenuates arterial baroreflex sensitivity in nonhuman primates.
Area of Science:
- Physiology
- Cardiovascular Research
Background:
- The arterial baroreflex is crucial for regulating blood pressure and heart rate.
- Intravascular volume expansion is a common clinical intervention.
Purpose of the Study:
- To investigate the impact of intravascular volume expansion on arterial baroreflex control of heart rate.
- To quantify changes in baroreflex sensitivity following volume expansion.
Main Methods:
- Conscious, instrumented nonhuman primates were used.
- Mean arterial blood pressure-pulse rate stimulus-response curves were generated before and after volume expansion.
- Regression analysis determined sigmoid curves and maximum sensitivity.
Main Results:
- Volume expansion involved administering a dextran solution equal to 20% of estimated blood volume.
- The mean arterial blood pressure-pulse rate curve shifted rightward at high blood pressures post-volume expansion.
- Maximum baroreflex sensitivity significantly decreased from 5.65 +/- 1.44 to 2.14 +/- 0.63 (P < 0.05).
Conclusions:
- Intravascular volume expansion attenuates baroreflex control of heart rate in conscious nonhuman primates.
- Reduced baroreflex sensitivity may have implications for cardiovascular regulation after fluid administration.