Fevurly R D, Spencer R L
Behavioral Neuroscience Program, Department of Psychology, University of Colorado at Boulder, 80309, USA.
J Neuroendocrinol. 2004 Dec;16(12):970-9. doi: 10.1111/j.1365-2826.2004.01257.x.
We examined the extent to which basal levels of corticosterone, which vary in a circadian fashion, influence the pattern of Fos protein expression in the paraventricular nucleus of the hypothalamus (PVN), the hippocampal formation and three different functional cortical areas. Basal and poststress (1 h of restraint) Fos expression, as determined by immunohistochemistry, was examined in male rats with either no previous surgical manipulation or in rats 5 days after: (i) sham adrenalectomy; (ii) adrenalectomy with no corticosterone replacement; or (iii) adrenalectomy with corticosterone (25 microg/ml) in the drinking water replacement. In adrenal-intact rats, restraint produced similar patterns of Fos expression in the PVN, cortical areas and hippocampus (CA1-CA3), with peak levels of expression attained 60-90 min after restraint onset. Surprisingly, in the dentate gyrus, there was a dissociation between the two blades in the pattern of Fos expression after restraint. In the inner blade (suprapyramidal), there was a delayed induction that occurred between 60 and 90 min after restraint onset and, in the outer blade (infrapyramidal), there was a steady decline in Fos expression after restraint. Adrenalectomy had an effect on Fos expression only in the PVN and dentate gyrus, and the nature of the effect was quite different for both brain regions. In the PVN, adrenalectomy had no effect on Fos expression in unstressed rats, but resulted in an enhanced number of Fos positive cells after restraint. In the dentate gyrus, adrenalectomy resulted in an overall reduction of Fos positive cells in both blades, and this reduction was present in unstressed and stressed rats. Corticosterone replacement normalized the adrenalectomy effect on Fos expression in both brain regions. Thus, Fos expression in the rat brain displays specific patterns of dependency on the permissive effects of glucorticoids, and this dependency varies between brain regions.
我们研究了以昼夜节律变化的皮质酮基础水平对下丘脑室旁核（PVN）、海马结构以及三个不同功能皮质区域中Fos蛋白表达模式的影响程度。通过免疫组织化学测定基础和应激后（1小时束缚）的Fos表达，实验对象为未进行过手术操作的雄性大鼠，或术后5天的大鼠，这些大鼠分为以下三组：（i）假肾上腺切除术；（ii）肾上腺切除术后不补充皮质酮；或（iii）肾上腺切除术后通过饮用水补充皮质酮（25微克/毫升）。在肾上腺完整的大鼠中，束缚应激在PVN、皮质区域和海马体（CA1 - CA3）产生了相似的Fos表达模式，束缚开始后60 - 90分钟达到表达峰值。令人惊讶的是，在齿状回中，束缚应激后Fos表达模式在两个叶之间出现了分离。在内侧叶（锥体上），束缚开始后60至90分钟出现延迟诱导，而在外侧叶（锥体下），束缚后Fos表达持续下降。肾上腺切除术仅对PVN和齿状回中的Fos表达有影响，且对这两个脑区的影响性质截然不同。在PVN中，肾上腺切除术对未应激大鼠的Fos表达没有影响，但在束缚应激后导致Fos阳性细胞数量增加。在齿状回中，肾上腺切除术导致两个叶中Fos阳性细胞总数减少，且这种减少在未应激和应激大鼠中均存在。补充皮质酮使肾上腺切除术对两个脑区Fos表达的影响恢复正常。因此，大鼠脑中Fos表达对糖皮质激素的允许作用呈现出特定的依赖模式，且这种依赖在不同脑区之间存在差异。
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