Fewell J E, Megirian D, Stobie-Hayes K M
Department of Physiology and Biophysics, University of Calgary, AB, Canada.
Can J Physiol Pharmacol. 1997 Feb;75(2):104-11. doi: 10.1139/cjpp-75-2-104.
Acute hypoxemia produces a decrease in body-core temperature (Tbc) in guinea pigs during postnatal maturation, although the factors mediating the response remain unknown. Experiments were therefore carried out to test the hypothesis that the carotid chemoreceptors and (or) baroreceptors mediate the decrease in Tbc during acute hypoxemia. Twelve guinea pigs, six carotid intact and six carotid denervated, were studied in a metabolic chamber to determine the influence of carotid denervation on the Tbc and metabolic (i.e., oxygen consumption) responses to changes in ambient temperature during normoxemia and during acute hypoxemia at 2, 3, and 4 weeks of age. Carotid denervation accentuated the decrease in Tbc in response to a decrease in ambient temperature during normoxemia at 2 and 3 weeks of age but not at 4 weeks of age without altering the metabolic response. This suggests that carotid denervation disrupted heat conservation mechanisms rather than heat production mechanisms in an age-specific manner. Furthermore, carotid denervation accentuated the decrease in Tbc and oxygen consumption in response to acute hypoxemia at all ages studied. This provides evidence that the carotid chemoreceptors and (or) baroreceptors do not mediate the decrease in Tbc that occurs in response to acute hypoxemia in guinea pigs during postnatal maturation.
急性低氧血症会使豚鼠在出生后成熟过程中体核温度（Tbc）下降，尽管介导这种反应的因素尚不清楚。因此，进行了实验以检验以下假设：颈动脉化学感受器和（或）压力感受器介导急性低氧血症期间Tbc的下降。在代谢室中对12只豚鼠进行了研究，其中6只颈动脉完整，6只颈动脉去神经支配，以确定颈动脉去神经支配对2、3和4周龄时正常氧血症和急性低氧血症期间环境温度变化时Tbc和代谢（即耗氧量）反应的影响。在2周龄和3周龄的正常氧血症期间，颈动脉去神经支配会加剧环境温度下降引起的Tbc下降，但在4周龄时不会，且不改变代谢反应。这表明颈动脉去神经支配以年龄特异性方式破坏了热保存机制而非产热机制。此外，在所有研究的年龄中，颈动脉去神经支配都会加剧急性低氧血症引起的Tbc和耗氧量下降。这提供了证据，表明颈动脉化学感受器和（或）压力感受器并不介导豚鼠出生后成熟过程中急性低氧血症引起的Tbc下降。
