Ventilation and Gas Exchange During Shallow Hypothermia in Pigeons
C. Jensen, C. Bech
Apr 1, 1992
Citations
8
Citations
Quality indicators
Journal
The Journal of Experimental Biology
Semantic Scholar
Key Takeaway Key Takeaway: Shallow hypothermia in domestic pigeons leads to a gradual development of respiratory acidosis, with parabronchial hypoventilation indicating effective parabronchial hypoventilation.
Abstract
Ventilatory control of the composition of the gases in the air sacs was studied during entry into fasting-induced, shallow, nocturnal hypothermia in the domestic pigeon ( Columba livia ). Respiratory frequency ( f ), tidal volume ( V T ) and oxygen uptake ( V O O2 were recorded simultaneously in six pigeons; partial pressures of CO 2 and O 2 in the abdominal and interclavicular air sacs were measured in seven pigeons. Ambient temperature was 25°C (thermoneutral) and the body temperature (Tb) was recorded in all experiments. A reduction in T b from 40.5 to 37.5°C paralleled decreases in f and V T from 13.3 min −1 and 15.2 ml BTPSkg −1 to 10.7 min −1 and 12.4ml BTPSkg −1 , respectively. There was a minor, but non-significant, simultaneous decrease in the ventilatory requirement (total ventilation/O 2 uptake) from 0.38 to O.35 ml BTPSmmol −1 . However, in both air sacs the partial pressure of CO 2 increased when T b decreased, indicating an effective parabronchial hypoventilation. The results support the idea of a gradually developing respiratory acidosis during hypothermia.