摘要
目的观察血管紧张素Ⅱ1型受体(AT1受体)细胞外第二环肽抗体对培养大鼠主动脉血管平滑肌细胞(VSMC)细胞质游离钙水平的影响。方法采用酶联免疫吸附测定法检测高血压患者血清中抗AT1受体抗体,亲和层析法提取阳性血清中的AT1受体细胞外第二环肽抗体。同时应用AT1受体胞外第二环肽主动免疫大鼠并提取抗体。将血管紧张素Ⅱ(AngⅡ),患者及大鼠的AT1受体胞外二环肽抗体分别刺激钙离子荧光探针Fluo-3/AM负载培养原代大鼠VSMC,观察荧光强度变化来检测细胞质游离钙水平变化。结果患者及大鼠血清中提取的AT1受体第二环肽抗体均刺激培养VSMC使细胞质游离钙水平升高,作用与AngⅡ类似。进一步实验发现抗体的激动效应能够被AT1受体胞外第二环肽的抗原表位序列及AT1受体拮抗剂氯沙坦阻断。结论针对AT1受体胞外第二环肽抗体具备激动效应,通过激动AT1受体刺激细胞质钙离子浓度增高,提示该抗体在高血压发病机制中起重要作用。
Objective To explore the effect of antibodies against the second extracellular loop of the angiotonin Ⅱ receptor type 1 （AT1 receptor） on the intracellular free Ca^2＋ level in rat vascular smooth muscle cells （VSMC）. Methods The antibodies against the second extracellular loop of the AT1 receptor from patients with hypertension were obtained by affinity chromatography. Rats were immunized with the second extracellular loop of the AT1 receptor to produce the antibodies against the peptide. Then, Fluo-3/AM, a Ca^2＋ fluorescent indicator, was used to load VSMC. Antibodies from both patients and rats were used to stimulate VSMC and the changes of fluorescence were monitored by confocal microscopy. Results VSMC showed increased intracellular free Ca^2＋ level induced by the patients＇ antibodies and rats＇ antibodies against the extracellular second loop of the AT1 receptor. Furthermore, the autoantibody-induced Ca^2＋ increase could be blocked by losartan, an AT1 receptor antagonist, and by a 7-amino-acid peptide that corresponds to a portion of the second extracel- lular loop of the AT1 receptor. Conclusion The study suggests that antibodies against the second extracellular loop of the AT1 receptor with the ability to activate the AT1 receptor may account for Ca^2＋ increase in VSMC. The autoantibodies against the AT1 receptor may be involved in the pathogenesis of hypertension.
出处
《中华老年心脑血管病杂志》
CAS
北大核心
2006年第11期752-755,共4页
Chinese Journal of Geriatric Heart,Brain and Vessel Diseases
基金
国家自然科学基金资助(G30300133)
关键词
高血压
血管紧张素Ⅱ
受体
血管紧张素
抗体
肌
平滑
血管
细胞质
hypertension
angiotensin Ⅱ
receptors, angiotensin
antibodies
muscle, smooth, vascular
cytoplasm
