Ageing and gonadectomy have similar effects on hypoglossal long-term facilitation in male Fischer rats
Ageing and gonadectomy have similar effects on hypoglossal long-term facilitation in male Fischer rats
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DOI：
10.1113/jphysiol.2004.077511
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发表时间：
2005-03-01
影响因子：
5.5
通讯作者：
Behan, A
中科院分区：
文献类型：
--
作者：
Zabka, AG;Mitchell, GS;Behan, A
长时程易化（LTF）是一种由间歇性低氧诱导的依赖于降钙素的呼吸可塑性，随着年龄的增长或雄性SD大鼠性腺切除术后LTF降低。衰老伴随着睾酮水平的下降，这反过来又影响了睾酮能功能。此外，年轻雄性大鼠的LTF在品系之间存在差异。因此，我们测试的假设，LTF是相似的中年和性腺切除的年轻雄性大鼠的近交系大鼠品系（F344）的研究中常用的老化（SD大鼠相比）。我们进一步测试了LTF的大小是否与睾酮和/或孕酮的循环血清水平相关。将年轻和中年完整和年轻性腺切除（GDX）雄性Fischer 344大鼠麻醉，神经肌肉阻滞和通气。综合膈神经和舌下神经（XII）的活动进行了测量之前，期间和60分钟后，三个5分钟的等二氧化碳缺氧事件。在青年和中年完整和青年GDX大鼠的膈运动输出中观察到LTF。相反，XII LTF仅在年轻的完整大鼠中观察到。青年和中年GDX大鼠的XII LTF显著低于青年正常大鼠（P < 0.05）。此外，XII LTF与睾酮/孕酮比值呈正相关。这些数据表明，在F344和SD大鼠品系中，上呼吸道呼吸输出中的降钙素依赖性可塑性是相似的。此外，LTF在中年和性腺切除的雄性大鼠中也同样受损，这表明性腺激素在调节上气道运动控制的神经可塑性能力中起重要作用。
Long-term facilitation (LTF), a form of serotonin-dependent respiratory plasticity induced by intermittent hypoxia, decreases with increasing age or following gonadectomy in male Sprague-Dawley (SD) rats. Ageing is accompanied by decreasing levels of testosterone, which in turn influences serotonergic function. In addition, LTF in young male rats differs among strains. Thus, we tested the hypothesis that LTF is similar in middle-aged and gonadectomized young male rats of an inbred rat strain commonly used in studies on ageing (F344) by comparison with SD rats. We further tested whether the magnitude of LTF correlates with circulating serum levels of testosterone and/or progesterone. Young and middle-aged intact and young gonadectomized (GDX) male Fischer 344 rats were anaesthetized, neuromuscularly blocked and ventilated. Integrated phrenic and hypoglossal (XII) nerve activities were measured before, during and 60 min following three 5-min episodes of isocapnic hypoxia. LTF was observed in phrenic motor output in young and middle-aged intact and young GDX rats. In contrast, XII LTF was observed only in young intact rats. In middle-aged and young GDX rats, XII LTF was significantly lower than in young intact rats (P < 0.05). Furthermore, XII LTF was positively correlated with the testosterone/progesterone ratio. These data show that serotonin-dependent plasticity in upper airway respiratory output is similar in F344 and SD rat strains. Furthermore, LTF is similarly impaired in middle-aged and gonadectomized male rats, suggesting that gonadal hormones play an important role in modulating the capacity for neuroplasticity in upper airway motor control.