A method for localizing intrapulmonary chemoreceptors in the parabronchial mantle of the duck

1. A method is presented for estimating the location of avian intrapulmonary chemoreceptors within the parabronchial mantle. 2. By determining the discharge frequency of a receptor at known receptor site Pco2's in a nonventilated but perfused lung, the receptor discharge could be calibrated to indicate the receptor site Pco2 during both ventilation and perfusion. 3. The relation among receptor site Pco2, mixed venous Pco2 and inspired Pco2 may be compared with calculated Pco2 profiles along the contact between air capillaries and blood capillaries and the receptor location may be determined as the relative distance between the luminal and peripheral ends of the air capillaries. 4. Of four receptors at the caudal end of a parabronchus, two were located at the terminal end of the air capillary and two along the peripheral half of the air capillary.