A prompt and sustained ventilatory output, greater than could be accounted for by the elevation of mean arterial carbon dioxide tension, occurred in response to a square-wave fluctuation of CO2 at the carotid bodies of dogs. Step perfusions with mean increments of 6.9 and 14.7 mm Hg Pco over control were associated with ventilation ratios of only 1.13 and 1.27, respectively. In contrast, during repeated square-wave perfusions, mean VR was 1.24 for a mean increment in Pco2 of only 4.9 mm Hg. The mean Pco2, of the square-wave perfusions was significantly lower than those of both step perfusions, and the mean VR of the square-wave perfusions was significantly higher than that of the lowest group of step perfusions. There was no evidence of adaptation of ventilation during the repeated square-wave perfusions. These findings support the concept that the pattern of application of a Co2 stimulus may provide an additional component to the chemical stimulus to respiration.
- Carbon dioxide forcing function
- Carotid body
- Control of respiration
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine