The carotid chemoreceptors are a major determinant of ventilatory CO 2 sensitivity and of PaCO2 during eupneic breathing

Abstract

Both carotid and intracranial chemoreceptors are critical to a normal ventilatory CO2-H+ chemosensitivity. At low levels of hypercapnia, the carotid contribution is probably greater than the central contribution but, at high levels, the intracranial chemoreceptors are dominant. The carotid chemoreceptors are also critical to maintaining a stable and normal eupneic PaCO2, but lesion-induced attenuation of intracranial CO 2-H+ chemosensitivity does not consistently alter eupneic PaCO 2. A major unanswered question is why do intracranial chemoreceptors in carotid body denervation (CBD) animals tolerate an acidosis during eupnea which prior to CBD elicits a marked increase in breathing. © 2008 Springer Science+Business Media, LLC.