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Hypoxia depletes ascorbate in the cat carotid body
1Department of Neurophysiology, Polish Academy of Sciences Medical Research Center, Warsaw, Poland. mp@ibbrain.ibb.waw.pl
Respiration Physiology
|March 1, 1997
Summary
Vitamin C (L-ascorbate) levels decrease in cat carotid bodies during low oxygen conditions, indicating its role in the chemosensing free radical mechanism. This finding is crucial for understanding cellular responses to hypoxia.
Area of Science:
- Biochemistry
- Physiology
- Neuroscience
Background:
- Vitamin C (L-ascorbate) acts as an endogenous reducing agent.
- It influences cellular functions tied to redox mechanisms, including oxygen tension detection by carotid body chemoreceptors.
Purpose of the Study:
- To investigate if ascorbate levels change in the carotid body due to its interaction with the chemosensing process.
- To determine if these changes are reflected in ascorbyl radical production.
Main Methods:
- Electron spin resonance (ESR) spectroscopy was used to examine ascorbyl radical changes.
- Carotid bodies were dissected from cats exposed to normoxic, hypoxic, and hypoxic-reoxygenated gas mixtures.
- ESR signal intensity was measured as peak-to-peak amplitude.
Main Results:
- ESR signal intensity decreased by 39% in hypoxia and 43% in hypoxic-reoxygenation compared to normoxia.
- Ascorbate was detected in normoxic carotid bodies and depleted under hypoxic conditions.
Conclusions:
- Ascorbate is present in the normoxic carotid body.
- Hypoxia leads to ascorbate depletion in the carotid body.
- Ascorbate is involved in the free radical mechanisms operating in the carotid body during hypoxia.