Shioda S, Iwase M, Homma I, Nakajo S, Nakaya K, Nakai Y
Department of Anatomy, Showa University School of Medicine, Tokyo, Japan.
Brain Res Bull. 1998 Mar 15;45(5):443-50. doi: 10.1016/s0361-9230(97)00342-0.
The present study demonstrates that projections ascending from the caudal ventrolateral medulla have direct effects on the expression of the immediate early gene c-fos and of the arginine-vasopressin gene in neurosecretory cells of the hypothalamic supraoptic nucleus. Intense Fos-like immunoreactivity (Fos-LI) was observed in many magnocellular neurons of the supraoptic nucleus after electrical stimulation of the caudal ventrolateral medulla. In sham-operated rats, Fos-LI was absent or present in very few magnocellular neurons in the supraoptic nucleus. Fos-LI was visible in neurons expressing arginine-vasopressin, and was seen rarely in oxytocin neurons by double-immunostaining method. This study showed that 76% of all Fos-positive cells were arginine-vasopressin immunoreactive, whereas only 4% of them showed oxytocin immunoreactivity in the supraoptic nucleus. With in situ hybridization, a high level of arginine-vasopressin mRNA was noted in the supraoptic nucleus 3 h after stimulation of the caudal ventrolateral medulla; the expression was highest 6 h after the stimulation compared with the same region in sham-operated animals. These findings suggest that noradrenaline, released from the axon terminals originating from the caudal ventrolateral medulla, may participate in the regulation of gene transcription of arginine-vasopressin in response to physiological stimuli.
本研究表明，从延髓尾端腹外侧区上行的投射对下丘脑视上核神经分泌细胞中即刻早期基因c-fos和精氨酸加压素基因的表达有直接影响。电刺激延髓尾端腹外侧区后，视上核的许多大细胞神经元中观察到强烈的Fos样免疫反应（Fos-LI）。在假手术大鼠中，视上核中极少有大细胞神经元存在Fos-LI或不存在Fos-LI。通过双重免疫染色法，在表达精氨酸加压素的神经元中可见Fos-LI，而在催产素神经元中很少见到。本研究表明，视上核中所有Fos阳性细胞的76%对精氨酸加压素有免疫反应性，而其中只有4%对催产素有免疫反应性。通过原位杂交，在刺激延髓尾端腹外侧区3小时后，视上核中精氨酸加压素mRNA水平较高；与假手术动物的同一区域相比，刺激后6小时表达最高。这些发现表明，从延髓尾端腹外侧区的轴突终末释放的去甲肾上腺素可能参与了精氨酸加压素基因转录的调节以响应生理刺激。
