RESPIRATORY RESPONSE TO HCL ACIDOSIS IN DOGS AFTER CAROTID-BODY DENERVATION

To test the participation of the carotid bodies in the respiratory response to metabolic acidosis, six dogs were infused with HCl for 2 h followed by HCl feeding to prolong the acidosis to 48 h. This protocol was repeated after carotid body denervation (CBD). Mean control PCO2 rose by 7.3 Torr after CBD. PCO2 fell comparably during acidosis before and after CBD at all the time periods from 30 to 48 h and returned to control levels by 72 h. The pH ranged from 7.10 to 7.30 during acidosis pre- and post-CBD. The decreases in pH and bicarbonate concentration did not differ significantly at any time interval between the pre- and post-CBD studies. This study indicates that in dogs moderately severe HCl acidosis stimulates ventilation acutely and chronically through a central mechanism in the absence of the carotid bodies.