切除大鼠肾上腺对丘脑下部CRF、VP和OT的影响——免疫组织化学研究

NFLUENCE OF ADRENECTOMY ON IMMUNOCHEMISTRY OF CRF, VP, AND OT IN HYPOTHALAMUS OF THE RAT

几乎只有向脑室内注入秋水仙素之后,才能在其丘脑下部室旁核(PVN)显示促肾上腺皮质激素释放因子(CRF)免疫反应神经元。然而,我们切除肾上腺也能显示这类神经元,而且其细胞数目在术后3周时明显多于1周。切除肾上腺又用秋水仙素处理,细胞的数目及其免疫反应强度增加得更加显著。切除肾上腺1、3周后,PVN前份背内侧区出现一群淡染的VP样神经元。术后PVN内OT样神经元无明显变化。在正中隆起(ME)处:切除肾上腺1周时,外带CRF样纤维免疫反应强度较正常明显减弱,3周时又恢复到正常水平。1周时减弱的原因本文作了推测。外带VP样纤维的免疫反应在术后1周时不减弱,而是增加,3周时增加得更明显。OT样纤维束居于ME内带,术后1周时没有明显变化,3周时其免疫反应有所增强。切除肾上腺后即用地塞米松治疗,结果PVN及ME内CRF、VP免疫反应与未治疗者比较,均受到不同程度的抑制。上述结果证明,肾上腺对CRF和VP均具有反馈抑制作用,并说明它们都参与了丘脑下部-腺垂体-肾上腺轴的调控。然而,对OT还需进一步研究。

The corticotropin releasing factor immunoreactive (CRFi)neurons were exposed in the hypothalamic paraventricular nuclei (PVN) almost only after intraventricular injection of colchicine. However, they could also be demonstrated in the 1st week and more obviously in the 3rd week after bilateral adrenalectomy. Still more cells occured when the operation was combined with the colchicine treatment. A group of weakly stained VP neurons appeared in the dorsomedial area of the anterior portion of the PVN in 1 and 3 weeks after adrenalectomy. OT neurons in the PVN showed no remarkable changes after operation. In the ME, the immunoreactivity of CRFi fibers were seen in the external zone (EZ) apparently decreased in the first postoperative week but restored almost to normal in the 3rd week. The reason for the decrease in the 1st week was discussed. The vasopressin immunoreactive (VPi) fibers seen in the EZ were not decreased, but increased in the 1st week and more markedly so in the 3rd week. The immunoreactivity of oxytocin (OTi) fiber tract in the internal zone (IZ) of ME showed no marked change, except that its immunoreactivity increased somewhat in the 3rd week. Dexamethasone treatment inhibited the immunoreactivity of the three peptidergic neurons and their fibers to a variable extent as compared with their controls. The results mentioned above indicate that CRF and VP are inhibited by adrenal feed back mechanism and that they participate in the action of hypothalamo-hypophyseal-adrenal-axis. But with regard to OT further studies should be done.