Segerson T P, Hoefler H, Childers H, Wolfe H J, Wu P, Jackson I M, Lechan R M
Endocrinology. 1987 Jul;121(1):98-107. doi: 10.1210/endo-121-1-98.
We studied the distribution of pro- TRH mRNA in rat brain by in situ hybridization histochemistry using radiolabeled single stranded cRNA probes to confirm the hypothesis that the TRH precursor is distributed beyond regions that contain immunoreactive TRH. All regions of the central nervous system previously recognized to contain TRH showed hybridization. Hypophysiotropic neurons in the medial parvocellular division of the paraventricular nucleus showed more intense hybridization than anterior parvocellular division cells, suggesting regional differences in expression. In addition, regions not previously recognized to contain TRH in neuronal perikarya by immunocytochemistry showed specific hybridization for pro-TRH mRNA. These include cells in the olfactory bulbs, dorsal motor nucleus of the vagus, ventrolateral periaqueductal gray, reticular nucleus of the thalamus, and anterior commissural nucleus. Only a single hybridizing band was observed on Northern blots of RNA extracts of the periaqueductal gray and reticular nucleus, identical to that seen in extracts of the paraventricular nucleus. The appearance of pro-TRH mRNA in neurons not previously recognized to contain TRH but which contain the prohormone suggests that non-TRH peptides within the TRH precursor may be preferentially expressed in certain regions of the brain.
我们采用放射性标记的单链cRNA探针，通过原位杂交组织化学技术研究了大鼠脑中促甲状腺激素释放激素原（pro-TRH）mRNA的分布，以证实TRH前体的分布超出含有免疫反应性TRH的区域这一假说。先前公认含有TRH的中枢神经系统所有区域均显示出杂交信号。室旁核内侧小细胞部的促垂体神经元显示出比前小细胞部细胞更强的杂交信号，提示表达存在区域差异。此外，免疫细胞化学先前未识别出神经元胞体中含有TRH的区域，显示出促甲状腺激素释放激素原mRNA的特异性杂交信号。这些区域包括嗅球、迷走神经背运动核、腹外侧导水管周围灰质、丘脑网状核和前连合核。在导水管周围灰质和网状核的RNA提取物的Northern印迹上仅观察到一条杂交带，与室旁核提取物中所见相同。促甲状腺激素释放激素原mRNA出现在先前未识别出含有TRH但含有该激素原的神经元中，这表明TRH前体中的非TRH肽可能在脑的某些区域优先表达。
