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A sympathetic pressor reflex in the conscious dog
Clinical Science (London, England : 1979)
|December 1, 1979
Summary
Mechanical activation of aortic sympathetic sensory fibers in dogs increased blood pressure and heart rate. This suggests positive feedback sympathetic reflexes are active in conscious animals.
Area of Science:
- Cardiovascular Physiology
- Autonomic Nervous System Research
Background:
- The role of aortic sympathetic sensory fibers in cardiovascular regulation is complex.
- Understanding these reflexes is crucial for managing blood pressure and heart rate.
Purpose of the Study:
- To investigate the effects of mechanical aortic wall stretch on sympathetic sensory fiber activity.
- To determine if these activations trigger cardiovascular responses in conscious, innervated animals.
Main Methods:
- Utilized a specialized cannula with an inflatable balloon implanted in the descending thoracic aorta of conscious dogs.
- Mechanically stretched the aortic walls to activate sensory fibers without impeding blood flow.
Main Results:
- Aortic wall stretch significantly elevated mean arterial blood pressure.
- Heart rate also showed a significant increase from baseline values.
- These cardiovascular changes occurred without any signs of pseudo-affective reactions.
Conclusions:
- Mechanical activation of aortic sympathetic sensory fibers elicits a positive feedback sympathetic reflex.
- This reflex pathway is functional in conscious, fully innervated animals.
- Findings contribute to understanding autonomic control of cardiovascular function.