ABSTRACT
The importance of intrapulmonary chemoreceptors (IPC), sensitive to 
in the lung, in the control of ventilatory movements is yet to be demonstrated in the self-ventilating bird. We distinguished between the effects of 
on IPC and on extrapulmonary CO2-sensitive receptors (EPC) in anaesthetized cockerels by denervating IPC in the right lung, ligating the left pulmonary artery and changing 
. Left IPC were thus exposed to a combination of 
from inspired gas and dead space, while EPC were exposed to greatly increased arterial 
resulting from the ventilation-perfusion inequality. At OTorr 
, steady state ventilatory depth and frequency did not change (P>0·5) after the ligation, although 
rose by 12·2 ± 1·7 Torr. After the ligation, ventilatory movements were more sensitive to increasing Pico,- Tracheostomy, which results in a greater decrease in 
in the innervated lung after ligation, produced greater effects. We conclude that these responses were due to the strong controlling influence of IPC on ventilatory movements in the self-ventilating cockerel.
