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Cl- replacement alters the ventilatory response to central chemoreceptor stimulation
T L Davidson1, M P Sullivan, K E Swanson
1Department of Biomedical Engineering, University of Virginia, Charlottesville 22908.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|January 1, 1993
Summary
Cerebrospinal fluid (CSF) chloride (Cl-) may influence respiratory control. Altering CSF ion composition, specifically reducing Cl-, impacted ventilation in rats, suggesting a role in central respiratory chemoreceptor stimulation.
Area of Science:
- Neuroscience
- Respiratory Physiology
Background:
- Central respiratory chemoreceptors monitor blood gases and pH to regulate breathing.
- The precise ionic mechanisms stimulating these chemoreceptors, particularly the role of chloride (Cl-), remain incompletely understood.
Purpose of the Study:
- To investigate the role of cerebrospinal fluid (CSF) chloride (Cl-) in modulating the stimulus to central respiratory chemoreceptors.
- To determine if Cl- transport influences ventilatory responses under conditions of constant CSF pH, CO2, and HCO3-.
Main Methods:
- Anesthetized rats were used, with the ventral medullary surface perfused with artificial cerebrospinal fluid (CSF).
- Perfusates varied in ion composition and pH, including solutions with reduced Cl- replaced by isethionate, an impermeant anion.
- Ventilatory parameters, including tidal volume and minute ventilation, were measured.
Main Results:
- Acidic perfusions with reduced Cl- (isethionate-containing) elicited significantly larger increases in tidal volume and minute ventilation compared to acidic perfusions with normal Cl- levels.
- These differences were observed despite identical CSF pH, PCO2, and HCO3- concentrations between the two acidic perfusions.
Conclusions:
- The findings suggest that Cl- transport plays a role in determining the stimulus to central respiratory chemoreceptors.
- Modulation of CSF Cl- levels may be a significant factor in regulating respiratory drive.