Aortic body chemoreceptor responses to dopamine, haloperidol

ceptor afferents to a range of arterial carbon dioxide tension (Pa & changes at various levels of arterial oxygen tension (Pao.,) were investigated in 18 cats anesthetized with cx-chlora-lose-and maintained at 38OC. Aortic chemoreceptor activity, end-tidal oxygen pressure, end-tidal carbon dioxide pressure, and arterial blood pressure were continuously monitored. Ar-terial blood gases were measured in steady states. Single or a few clearly identifiable afferents were studied during changes and steady states of Pao, and PacoY. All the aortic chemore-ceptor afferent discharge rates increased with Pace, increases from hypocapnia (lo-15 Tort) to normocapnia and moderate hypercapnia (30-50 Torr) and with Pao., decreases from above 400 to 30 Torr. Hypoxia augmented the response toPaco, most effectively in the range of lo-40 Torr. At any Pao,, the discharge rate reached a plateau with sufficient intensity of hypercapnia