Avishai-Eliner S, Yi S J, Baram T Z
Division of Critical Care, Children's Hospital Los Angeles, CA 90027, USA.
Brain Res Dev Brain Res. 1996 Feb 26;91(2):159-63. doi: 10.1016/0165-3806(95)00158-1.
The ontogeny of corticotropin-releasing hormone (CRH) receptor messenger ribonucleic acid (mRNA) in rat brain, using in situ hybridization, is the focus of this study. The developmental profile of CRH receptor using binding assays and receptor autoradiography has been reported, but may be confounded by the presence of a binding protein. The recent cloning of the rat CRH receptor gene has permitted the use of in situ hybridization histochemistry to map the distribution of cells expressing CRH receptor mRNA in the developing brain. We used antisense 35S-labeled oligodeoxynucleotide probes for the two reported splice-variants of the CRH receptor mRNA, which yielded essentially identical localization patterns. CRH receptor mRNA was clearly detectable in infant brain starting on the second postnatal day. Signal in hippocampal CA1, CA2 and CA3a increased to 300-600% of adult levels by postnatal day 6 with a subsequent gradual decline. In the amygdala, in contrast, CRH receptor mRNA abundance increased steadily between the second and the ninth postnatal days, to levels twice higher than those in the adult. In the cortex, CRH receptor mRNA levels were high on postnatal day 2 and decreased to adult levels by day 12. Transient signal over the hypothalamic paraventricular nucleus, observed on the second postnatal day, was not evident at older ages. These results demonstrate robust synthesis of CRH receptor as early as on the second postnatal day and unique region-specific developmental profiles for CRH receptor gene expression.
本研究的重点是利用原位杂交技术研究大鼠脑中促肾上腺皮质激素释放激素（CRH）受体信使核糖核酸（mRNA）的个体发生。已报道了使用结合测定和受体放射自显影技术对CRH受体进行的发育概况研究，但可能会因结合蛋白的存在而混淆。大鼠CRH受体基因的近期克隆使得能够使用原位杂交组织化学技术来绘制发育中大脑中表达CRH受体mRNA的细胞分布图谱。我们使用了针对CRH受体mRNA的两种报道的剪接变体的反义35S标记寡脱氧核苷酸探针，它们产生了基本相同的定位模式。出生后第二天开始在幼鼠脑中就可清晰检测到CRH受体mRNA。海马CA1、CA2和CA3a区的信号在出生后第6天增加到成年水平的300 - 600%，随后逐渐下降。相比之下，在杏仁核中，CRH受体mRNA丰度在出生后第2天到第9天之间稳步增加，达到比成年水平高两倍的水平。在皮质中，CRH受体mRNA水平在出生后第2天高，到第12天降至成年水平。在出生后第二天观察到的下丘脑室旁核上的短暂信号在较大年龄时不明显。这些结果表明，早在出生后第二天就有强大的CRH受体合成，并且CRH受体基因表达具有独特的区域特异性发育概况。
