Central respiratory chemoreceptor (CRC)

Central respiratory chemoreceptors are specialized clusters of neurons, primarily located in the retrotrapezoid nucleus (RTN) and other regions of the ventrolateral medulla, that monitor the chemical composition of the brain's extracellular fluid (Nattie and Li, 2012). Their primary function is to sense changes in the partial pressure of carbon dioxide (PCO2) and the resulting fluctuations in hydrogen ion concentration (pH) (Guyton and Hall, 2020). When CO2 levels rise, these receptors trigger an increase in ventilatory drive to restore acid-base homeostasis (StatPearls, 2023). Molecularly, this sensing is mediated by specific proteins such as the G protein-coupled receptor GPR4, the proton-sensitive potassium channels TASK-1 and TASK-3, and the enzyme carbonic anhydrase (Kumar et al., 2015). Dysfunction of these chemoreceptors is a hallmark of Congenital Central Hypoventilation Syndrome (CCHS) and contributes to the pathogenesis of obstructive and central sleep apnea (Nattie and Li, 2012). Pharmacological agents like doxapram stimulate these receptors to treat respiratory depression, while opioids and sedatives can dangerously suppress their activity, leading to life-threatening hypoventilation (StatPearls, 2023).

Other names

Medullary chemoreceptorCentral chemosensorCO2-sensitive medullary neuronsBrainstem chemoreceptor

Modulation of medullary neuronal excitability in response to changes in extracellular pH and PCO2 to regulate ventilatory output.