Hypercapnia causes cellular oxidation and nitrosation in addition to acidosis: implications for CO2 chemoreceptor...

Area of Science:

• Neuroscience
• Respiratory Physiology
• Biochemistry

Background:

• Cellular mechanisms of CO2 chemoreception are debated, focusing on protons from CO2 hydration.
• Molecular CO2 also reacts with reactive nitrogen species (RNS), producing oxidative and nitrosative intermediates.
• Protons further drive redox reactions, generating reactive oxygen species (ROS).

Purpose of the Study:

• To summarize nitrosative and oxidative reactions during hypercapnic and isocapnic acidosis.
• To review evidence for redox signaling in chemosensitive areas.
• To examine evidence that neurons in the solitary complex are stimulated by cellular oxidation.

Main Methods:

• Literature review and synthesis of existing research on CO2 chemoreception.
• Analysis of biochemical reactions involving CO2, protons, ROS, and RNS.
• Examination of studies on cardiorespiratory control and neuronal stimulation.

Main Results:

• CO2 triggers not only proton-based but also ROS/RNS-mediated signaling pathways.
• Neurons in chemosensitive areas produce ROS/RNS, suggesting their role in chemoreception.
• Cellular oxidation stimulates neurons in the solitary complex, a key chemosensitive area.

Conclusions:

• pH and ROS/RNS may act synergistically to stimulate CO2 chemoreceptors during hypercapnic acidosis.
• Nitrosative and oxidative stress could contribute to CO2 chemoreceptor dysfunction.
• Understanding these redox mechanisms is crucial for comprehending central chemoreception and related disorders.