Morici G, Licciardi A, Leandro G
Istituto di Fisiologia Umana della Università di Palermo.
Boll Soc Ital Biol Sper. 1990 Apr;66(4):397-404.
Changes in respiratory frequencies with hypoxic or hyperoxic exposure were studied in: 12 normoxic control rats (N) born and raised in normoxic environment at sea level; 12 rats (A) born and raised in normoxic environment at sea level exposed to normobaric hypoxia (10% O2 in N2) as adults; 12 rats of first generation (G1) raised in the above mentioned hypoxic environment since a few hours after birth; 12 rats of third generation (G3) conceived and born in the hypoxic environment of hypoxic parents of second generation and maintained continuously under hypoxic conditions until their utilization. The response of A rats to 10% O2 and 7% O2 breathing was elevated (57% and 86% over air breathing). The mean respiratory frequency of A rats exposed to 7% O2 rose to a greater extent than did that of N rats. The G1 and G3 rats were less responsive to 7% O2 (64% and 37% over air breathing, respectively) than N and A rats; however, in G1 rats the exposure to 7% O2 produced a greater rise of frequency than in G3 rats. Furthermore A rats, G1 rats and G3 rats were less responsive to 97% O2 breathing (19%, 19% and 11% below air breathing, respectively). Comparing these data with previous findings we suggest that, with chronic exposure to hypoxia, changes in ventilatory response to hypoxia and hyperoxia occur in the following manner: I) loss of response to hypoxia if chronic exposure is begun in the immediate postnatal period; 2) degree of response to hypoxia or hyperoxia influenced by duration of chronic exposure.
研究了常氧、低氧或高氧暴露下呼吸频率的变化，实验对象包括：12只常氧对照大鼠（N），在海平面常氧环境中出生并饲养；12只大鼠（A），在海平面常氧环境中出生并饲养，成年后暴露于常压低氧环境（氮气中10%氧气）；12只第一代大鼠（G1），自出生后数小时起在上述低氧环境中饲养；12只第三代大鼠（G3），在第二代低氧亲本的低氧环境中受孕并出生，持续处于低氧条件下直至用于实验。A组大鼠对10%氧气和7%氧气呼吸的反应增强（比空气呼吸分别高57%和86%）。暴露于7%氧气时，A组大鼠的平均呼吸频率升高幅度大于N组大鼠。与N组和A组大鼠相比，G1组和G3组大鼠对7%氧气的反应性较低（分别比空气呼吸高64%和37%）；然而，G1组大鼠暴露于7%氧气时频率升高幅度大于G3组大鼠。此外，A组大鼠、G1组大鼠和G3组大鼠对97%氧气呼吸的反应性较低（分别比空气呼吸低19%、19%和11%）。将这些数据与之前的研究结果进行比较，我们认为，长期暴露于低氧环境下，对低氧和高氧的通气反应变化如下：I）如果在出生后立即开始长期暴露于低氧环境，对低氧的反应丧失；2）对低氧或高氧的反应程度受长期暴露持续时间的影响。
