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Aortic diastolic caliber changes as a determinant for complete aortic baroreceptor resetting
Federation Proceedings
|January 1, 1987
Summary
Baroreceptors in hypertensive rats reset rapidly but completely within 48 hours. Aortic dilation timing closely matches this complete baroreceptor resetting, suggesting its role in hypertension adaptation.
Area of Science:
- Cardiovascular Physiology
- Hypertension Research
- Neuroscience
Background:
- Baroreceptors are crucial for blood pressure regulation.
- Baroreceptor resetting is known to occur in hypertension but its mechanisms and time course are unclear.
- Acute partial resetting occurs within minutes, while complete resetting requires sustained pressure changes.
Purpose of the Study:
- To investigate the time course and mechanisms of baroreceptor resetting in hypertension.
- To examine the relationship between aortic caliber changes and baroreceptor resetting.
- To understand the role of aortic distension in baroreceptor adaptation during hypertension.
Main Methods:
- Studied baroreceptor resetting in freely moving rats.
- Induced sustained hypertension using subdiaphragmatic aortic constriction.
- Monitored aortic caliber changes using imaging techniques.
- Assessed baroreceptor activation thresholds at different time points.
Main Results:
- Complete baroreceptor resetting to hypertension in rats occurred within 48 hours.
- Maximal aortic diastolic caliber dilation coincided with complete baroreceptor resetting.
- Aortic caliber displacement significantly exceeded pulse pressure changes during acute pressure increases.
Conclusions:
- Sustained hypertension leads to complete baroreceptor resetting within 48 hours in rats.
- Aortic distensibility plays a significant role in the resetting of aortic baroreceptors.
- The resting diastolic caliber of the aorta is a key factor in baroreceptor distortion and adaptation to pressure changes.