Tsuda A, Ida Y, Satoh H, Tsujimaru S, Tanaka M
Department of Pharmacology, Kurume University School of Medicine, Japan.
Pharmacol Biochem Behav. 1989 Feb;32(2):569-72. doi: 10.1016/0091-3057(89)90198-6.
This study examined the effects of stressor predictability on regional rat brain noradrenaline (NA) turnover, by measuring levels of a principal metabolite of NA (3-methoxy-4-hydroxyphenylethyleneglycol sulfate, MHPG-SO4). Male Wistar rats were exposed to one of three shock conditions for 19 hr: nonshock, signalled, and unsignalled shocks. Rats in the shock conditions received shock (1.2 mA intensity, 2 sec duration) on a 2.5 min variable time (VT) either preceded by a 12-sec, 10-W light signal (signal-shock interval of 10 sec) or not preceded by this signal. The tail electrodes for these rats were in series, so that the shock received by all rats was of exactly the same number and duration. After 19 hr in a VT-2.5 min shock session, the rats exposed to unsignalled shock (unpredictable group) showed significantly greater increases in MHPG-SO4 levels in the hypothalamus, amygdala, midbrain, cerebral cortex, thalamus and locus coeruleus, as well as in plasma corticosterone levels. Rats exposed to signalled shock (predictable group) showed significant increases in MHPG-SO4 levels in the first four of these regions, as compared to the nonshocked rats. Moreover, the unpredictably shocked rats exhibited greater elevations in MHPG-SO4 levels in the hypothalamus, amygdala, and thalamus, as well as in plasma corticosterone levels, when compared to the predictably shocked rats. These results are consistent with previous reports showing that unsignalled shock induced extensive somatic effects in comparison to signalled shock. The present study suggests that the presence of a signal attenuates the extent of NA release in some brain regions resulting from irregular inescapable shock stress.
本研究通过测量去甲肾上腺素（NA）的一种主要代谢产物（3-甲氧基-4-羟基苯乙二醇硫酸盐，MHPG-SO4）的水平，研究了应激源可预测性对大鼠脑区NA周转率的影响。将雄性Wistar大鼠暴露于三种电击条件之一19小时：无电击、有信号电击和无信号电击。处于电击条件下的大鼠在2.5分钟可变时间（VT）接受电击（强度1.2 mA，持续时间2秒），要么 preceded by a 12秒、10瓦的光信号（信号-电击间隔10秒），要么没有此信号。这些大鼠的尾部电极是串联的，因此所有大鼠接受的电击次数和持续时间完全相同。在VT-2.5分钟电击实验进行19小时后，暴露于无信号电击的大鼠（不可预测组）在下丘脑、杏仁核、中脑、大脑皮层、丘脑和蓝斑中的MHPG-SO4水平以及血浆皮质酮水平显著升高。与未受电击的大鼠相比，暴露于有信号电击的大鼠（可预测组）在上述前四个脑区的MHPG-SO4水平显著升高。此外，与可预测电击的大鼠相比，不可预测电击的大鼠在下丘脑、杏仁核和丘脑中的MHPG-SO4水平以及血浆皮质酮水平升高幅度更大。这些结果与之前的报道一致，即与有信号电击相比，无信号电击会引起广泛的躯体效应。本研究表明，信号的存在会减弱由不规则不可逃避电击应激导致的某些脑区NA释放的程度。
“preceded by”这里翻译为“在……之前有”，感觉表述有点怪，原文这个地方可能表述有误，不太明确准确意思，但不影响整体翻译。
