大鼠正中视前核注射血管紧张素Ⅱ对近曲小管Na^+,K^+-ATPase活性的影响  

Effect of MnPO microinjection of Ang Ⅱ on Na^+,K^+-ATPase activity of proximal tubule in rats

作　　者：罗蕾[1] 刘红[2] 刘爱东[1] 高原[3] 

机构地区：[1]遵义医学院生理学教研室,贵州遵义563003 [2]川北医学院生理学教研室,四川南充637000 [3]遵义医学院珠海校区机能学教研室,广州珠海519041

出　　处：《遵义医学院学报》2009年第3期218-221,共4页Journal of Zunyi Medical University

基　　金：珠海市科技基金资助项目(PC2003010057)

摘　　要：目的探讨大鼠正中视前核(MnPO)的血管紧张素Ⅱ(AngⅡ)对肾脏近曲小管Na+,K+-ATPase活性的作用及其途径。方法雄性SD大鼠,麻醉下MnPO注射AngⅡ,或预先注射AngⅡ的Ⅰ型受体(AT1)拮抗剂氯沙坦(Losartan)后再注射AngⅡ。注射后45min取血,放射免疫分析法测定血清内源性洋地黄样物质(EDLS)水平;立体显微镜下手工微分离单根近曲小管,电镜鉴定,液闪计数器测定近曲小管Na+,K+-ATPase活性。结果与MnPO注射aCSF的结果比较,在MnPO注射AngⅡ后45min,血清EDLS水平显著升高(59.87±4.48)pg/mLvs.(42.86±4.0)pg/mL,P<0.05;近曲小管Na+,K+-ATPase活性显著降低(1327±127)pmolPi/mm/hvs.(1788±118)pmolPi/mm/h,P<0.05;近曲小管Na+,K+-ATPase活性下降幅度与血清EDLS升高幅度呈负相关(r=-0.945,P<0.05);而Losartan预处理MnPO再注射AngⅡ后45min,血清EDLS水平和近曲小管Na+,K+-ATPase活性均无显著变化。结论AngⅡ通过作用于MnPO的Ⅰ型受体(AT1),可抑制肾小管的Na+,K+-ATPase活性,AngⅡ的这一作用与其促进EDLS的释放有关。The present study was designed to explore both the effect and access of the angiotensin II （ Ang II ）in the median preoptie nucleus （MnPO）on Na^＋,K^＋ -ATPase activity of proximal tubule in rats.Studies were performed on anesthetized SD rats and MnPO injection was carried out by a stainless steel tube planted on the accurate site in the rat brain through a stereotactic apparatus.According to injection of MnPO with aCSF,AnglI,Losartan and Angll. EDLS level in serum was assessed by radioimmunoassay （RIA） . The single proximal tubules were microdissected by freehand and examined using scanning electron microscope.The Na^＋,K^＋ -ATPase activity in proximal tubules was determined by liquid scintillation counter （LSC）. The results demonstrated injection of aCSF into the MnPO caused only minor effects,whereas AnglI significantly increased serum EDLS level on 45min（59.87±4.48）pg/mL vs. （42.86±4.0）pg/mL, P〈0.05 and proximal tubule Na^＋,K^＋ -ATPase activity responses to AnglI decreased （1327±127） pmol Pi/mm/h vs.（1788±118）pmol Pi/mmlh, P〈0.05.There was a negative linear correlation between EDLS and proximal tubule Na^＋,K^＋ -ATPase activity （r=-0.945, P〈0.05）.The result of the present investigation suggests that central Ang II may stimulate and modulate EDLS release,acting directly upon MnPO which is an important receptive site for Angll,eonsequently the Na^＋,K^＋ -ATPase of proximal tubule is alternated.

关 键 词：正中视前核 血管紧张素Ⅱ 近曲小管 Na+ K+-ATPase 内源性洋地黄样物质 大鼠 

分 类 号：R334.1[医药卫生—人体生理学]