An extravagal respiratory reflex from nociceptors of the lungs

Limited injury to the parenchyma of the lungs before vagotomy intensifies the inspiratory volleys of the diaphragm and reduces the respiration rate. Similar injury to the lungs in vagotomized animals only intensifies the inspiratory volleys, for the respiration rate changes, if at all, not significantly. The increase in the depth of respiration caused by stimulation of the lung nociceptors innervated by extravagal fibers would appear to be very important for pulmonary ventilation and is provided most satisfactorily by deep breathing. Probably not only the afferent fibers of the vagus nerves but also afferents running in the composition of the extravagal nerves must be taken into account when relations between the depth and frequency of respiration in the pulmonary ventilation are analyzed, especially under pathological conditions.