Metabolic and ventilatory adjustments and tolerance of the bat Pteropus poliocephalus to acute hypoxic stress.
We have investigated the maximum tolerance and the ventilatory responses of a bat, P. poliocephalus (PP), to normobaric hypoxic stress. PP can tolerate inspired PO2s (PiO2) down to 30 torr. This bat is one of the most hypoxia-tolerant non-hibernating species of mammals known, and has a tolerance which lies within the range of PiO2s reported for different birds. Unlike most mammals in its size range, PP maintains its normoxic oxygen consumption rate even in deep hypoxia. The maximum hypoxic ventilatory response (HVR), the air convection requirement (Vi/MO2), and the lung oxygen extraction (EL) ability of PP in deep hypoxia are all greater than those of other mammals. These and other data indicate that PP has a superior mammalian tolerance for hypocapnia. The magnitudes of both the V1/MO2 and the EL value of PP fall between those reported for Pekin ducks at corresponding PiO2s, and are inferior to the maximum capabilities of bar-headed geese. Thus, the tolerance and ventilatory adjustments of PP to deep hypoxia are intermediate between those of typical non-flying mammals and the most tolerant avian species, and suggest that at least some of this bat's respiratory adaptations for flight may serve as preadaptations for withstanding acute hypoxic stress.
Thomas
S P
SP
Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282-1502, USA.
Follette
D B
DB
Thomas
G S
GS
D000208:Acute Disease; D000222:Adaptation, Physiological; D000818:Animals; D002685:Chiroptera / Q000378:metabolism* / Q000502:physiology*; D005260:Female; D008168:Lung / Q000503:physiopathology; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D012119:Respiration; D013312:Stress, Physiological / Q000503:physiopathology*
D010100:Oxygen