Increases in the activity of tryptophan hydroxylase from rat cortex and midbrain in response to acute or repeated sound stress are blocked by adrenalectomy and restored by dexamethasone treatment.
Increases in the activity of tryptophan hydroxylase from rat cortex and midbrain in response to acute or repeated sound stress are blocked by adrenalectomy and restored by dexamethasone treatment.
复制标题
大鼠皮质和中脑响应急性或重复声音应激而增加的色氨酸羟化酶活性的增加被肾上腺切除术阻断，并通过地塞米松治疗恢复。
DOI：
10.1016/0006-8993(90)90898-l
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发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Boadle-Biber,MC
中科院分区：
文献类型：
--
作者：
Singh,VB;Corley,KC;Phan,TH;Boadle-Biber,MC
将雄性 Sprague-Dawley 大鼠暴露于急性声音应激（2 秒，每分钟随机出现 110 dB 声音脉冲，持续 1 小时）会通过碱性磷酸酶可逆机制增加皮质和中脑色氨酸羟化酶的体外活性。连续三天重复暴露于声音压力会导致酶活性稳定增加，这种活性在压力终止后持续 24 小时，并且对碱性磷酸酶不敏感。肾上腺切除术消除了急性或重复声音应激引起的酶活性增加，但不改变酶活性的基线水平。肾上腺切除术后第 3 天开始，合成糖皮质激素地塞米松（500 μg/天，腹腔注射）给药 3 天或 6 天中的 5 天，可恢复分别暴露于急性或重复声音应激的肾上腺切除大鼠酶活性的增加。在急性声音应激、肾上腺切除的大鼠中，盐皮质激素醛固酮（5 μg/天，皮下注射）不能替代地塞米松。地塞米松不会改变肾上腺切除大鼠或肾上腺完整的大鼠（假肾上腺切除）中酶活性的控制水平，但需要使酶活性增加以响应急性或重复的声音应激。因此，糖皮质激素的作用似乎是一种允许的作用。
Exposure of male Sprague-Dawley rats to acute sound stress (2 s, 110 dB sound pulses presented randomly every minute for 1 h) increases the in vitro activity of cortical and midbrain tryptophan hydroxylase by an alkaline phosphatase-reversible mechanism. Repeated exposure to sound stress on three separate days produces a stable increase in enzyme activity that persists 24 h after the termination of the stress and is insensitive to alkaline phosphatase. Adrenalectomy abolishes both increases in enzyme activity to acute or repeated sound stress but does not change baseline levels of enzyme activity. The synthetic glucocorticoid, dexamethasone, (500 μg/day i.p.) given for 3 days or 5 out of 6 days, starting day 3 after adrenalectomy, restores the increases in enzyme activity in adrenalectomized rats exposed, respectively, to acute or repeated sound stress. The mineralocorticoid, aldosterone (5 μg/day s.c.), does not substitute for dexamethasone in acutely sound-stressed, adrenalectomized rats. Dexamethasone does not alter control levels of enzyme activity in either adrenalectomized rats or rats with intact adrenals (sham-adrenalectomized), but is required to allow the increase in enzyme activity in response to acute or repeated sound stress to be expressed. The effect of the glucocorticoid, thus, appears to be a permissive one.