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Peripheral vascular responses to hypoxic hypoxia after aortic denervation
Canadian Journal of Physiology and Pharmacology
|September 1, 1985
Summary
Aortic chemoreceptors and vagal afferent nerves are crucial for circulatory adjustments during hypoxic hypoxia, primarily impacting cardiac output via venous effects. They do not influence skeletal muscle blood flow responses to low oxygen.
Area of Science:
- Cardiovascular Physiology
- Respiratory Physiology
- Neuroscience
Background:
- Hypoxic hypoxia triggers complex circulatory adjustments.
- The role of aortic chemoreceptors and vagal afferent pathways in these responses requires clarification.
Purpose of the Study:
- To investigate the essential role of aortic chemoreceptors and vagal afferent traffic in circulatory adjustments to hypoxic hypoxia.
Main Methods:
- Anesthetized dogs underwent aortic denervation (AD), bilateral cervical vagotomy (V), or sham operation.
- Animals were ventilated with hypoxic air (9% O2).
- Cardiac output, hindlimb blood flow, and arterial pressures were monitored.
Main Results:
- Cardiac output response to hypoxia was attenuated in AD and V groups.
- Hindlimb blood flow increased similarly across all groups.
- The initial pressor response to hypoxia was abolished in AD and V groups.
Conclusions:
- Aortic chemoreceptor stimulation during hypoxia augments cardiac output, mainly through venous effects.
- Vagal afferent pathways are essential for these cardiac output adjustments.
- These pathways do not play a role in skeletal muscle vascular responses to hypoxic hypoxia.