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Respiratory control by ventral surface chemoreceptor neurons in rats
Daniel K Mulkey1, Ruth L Stornetta, Matthew C Weston
1Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA.
Nature Neuroscience
|November 24, 2004
Summary
Researchers identified carbon dioxide (CO2)-sensitive neurons in the rat retrotrapezoid nucleus (RTN). These neurons are strong candidates for the central chemoreceptors that detect CO2 and regulate breathing.
Area of Science:
- Neuroscience
- Respiratory Physiology
Background:
- Central chemoreception, crucial for regulating breathing, is thought to involve neurons on the ventral medulla.
- Identifying these specific chemoreceptor neurons has been a long-standing challenge in neuroscience.
Purpose of the Study:
- To identify and characterize neurons responsible for central chemoreception in the ventral medulla.
- To determine if neurons in the retrotrapezoid nucleus (RTN) function as central CO2 chemoreceptors.
Main Methods:
- In vivo and in vitro electrophysiological recordings in rats.
- CO2 and pH sensitivity testing of RTN neurons.
- Pharmacological blockade of respiratory centers and carotid body denervation.
Main Results:
- Glutamatergic RTN neurons were vigorously activated by CO2 in vivo, unlike serotonergic neurons.
- CO2 sensitivity of RTN neurons persisted independently of respiratory pattern generators and carotid body input.
- A subset of RTN neurons in brainstem slices showed intrinsic pH sensitivity, activated by acidification and CO2.
Conclusions:
- Neurons within the rat retrotrapezoid nucleus (RTN) exhibit characteristics of central CO2 chemoreceptors.
- These RTN neurons are likely involved in detecting CO2 and regulating breathing.
- The findings identify specific neuronal populations crucial for respiratory control and CO2 homeostasis.