Acclimatization to high altitude in goats with ablated carotid bodies.

In awake goats with ablated carotid bodies, we studied resting pulmonary ventilation, CO2 production, composition of arterial blood and cerebrospinal fluid (CSF), and ventilatory responsiveness to hyperoxic CO2 rebreathing at sea level (SL) and after 3 days at simulated high altitude (HA) (PB 446 +/- 5 Torr, equivalent to 4,300 m). At HA, resting pulmonary ventilation was increased, resulting in marked hypocapnia with appropriate base deficit in blood plasma; CSF became more alkaline; CO2-response curves were shifted to lower PCO2 levels, and their slopes were steeper than at SL. Although these changes in regulation of respiration were not demonstrably different from those seen after normal acclimatization to HA with carotid bodies intact, the mechanisms of their initiation and development are probably different.