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Chemoreceptor stimulation interferes with regional hypoxic pulmonary vasoconstriction
M W Chapleau1, L B Wilson, T J Gregory
1Department of Physiology, Louisiana State University Medical Center, New Orleans 70112-1393.
Respiration Physiology
|February 1, 1988
Summary
Selective stimulation of arterial chemoreceptors can interfere with hypoxic vasoconstriction in the lungs. Vagus nerves appear to mediate this effect, impacting blood flow diversion during low oxygen conditions.
Area of Science:
- Physiology
- Cardiovascular System
- Respiratory System
Background:
- Hypoxemia impairs blood flow diversion in hypoxic lung regions.
- Arterial chemoreceptor reflex activation is a potential mechanism.
Purpose of the Study:
- To determine if selective carotid chemoreceptor stimulation reduces hypoxic vasoconstriction.
- To investigate the role of vagus nerves in this response.
Main Methods:
- Anesthetized dogs with isolated lung ventilation.
- Measurement of pulmonary blood flow using electromagnetic flow probes.
- Selective carotid chemoreceptor stimulation with hypoxic, hypercapnic blood.
Main Results:
- Selective chemoreceptor stimulation did not reduce hypoxic vasoconstriction in dogs with intact vagi.
- In vagotomized dogs, hypoxic vasoconstriction was reduced by chemoreceptor stimulation.
- These effects were consistent with or without cyclo-oxygenase inhibition.
Conclusions:
- Selective arterial chemoreceptor stimulation can interfere with regional hypoxic vasoconstriction.
- Vagus nerves likely mediate the inhibitory effect of chemoreceptor stimulation on hypoxic vasoconstriction.