Carotid chemoreceptor response to intermittent or sustained stimulation in the cat

In order to determine how closely the carotid chemoreceptor system follows a repeated transient stimulus, intermittent infusions of hypercapnic-hypoxic, hypercapnic, and hypoxic blood were made into the common carotid arteries of anesthetized, artificially ventilated cats. The system demonstrated an ability to follow blood-home stimuli presented at frequencies up to about 70 min^-1 though at decreasing amplitude. In response to sustained stimulations, the carotid body showed a slow adaptation to hypercapnic stimuli and perhaps to hypoxic stimuli also. A transient undershoot occurred at the cessation of stimulation when the animal was breathing air, an event generally not seen if the animal was breathing pure oxygen.