心房特殊颗粒是一种细胞内钙库  

ATRIAL SPECIFIC GRANULES ARE AN INTRACELLULAR CALCIUM STORE

作　　者：钟慈声[1] 俞彰[1] 俞雯倩[1] 凌诒萍[1] 

机构地区：[1]上海医科大学生物物理教研室

出　　处：《生理学报》1994年第1期30-35,共6页Acta Physiologica Sinica

基　　金：国家自然科学基金

摘　　要：研究心房钠尿肽分泌过程是否与心房特殊颗粒中钙的释放有关，需首先阐明心房特殊颗粒是否含有高浓度钙。本工作用电镜Ｘ射线显微分析技术定量地测定心房特殊颗粒中钙的浓度。新鲜大鼠心房经快速冷冻后作冷冻超薄切片，在ＪＥＭ－１２００ＥＸ分析电镜（附有ＬｉｎｋＡＮ１００００能量分散型Ｘ射线分光仪）下进行测定。１０次测定结果显示心房特殊颗粒含较高浓度的钙，平均值达８１±１５ｍｍｏｌ／ｋｇ，接近肌质网中钙的浓度。用Ｃａ２＋－ＡＴＰ酶电镜细胞化学技术证实酶反应产物存在于心房特殊颗粒的包膜上。推想颗粒包膜上的Ｃａ２＋－ＡＴＰ酶能将钙从胞质溶胶中推向颗粒内，并维持颗粒内的高钙浓度。因此认为心房特殊颗粒是心房肌细胞中的又一种细胞内钙库。In order to elucidate whether the secretion of atrial natriuretic peptide(ANP) is correlated to the release of calcium (Ca) from the atrial specific granules(ASG), it is necessary to explore whether the ASG contain highly concentrated Ca and how the high Ca is maintained in the ASG. The present study was designed to determine Ca in the ASG with the quantitative electron microscope X-ray microanalysis and Ca2+-ATPase with electron microscopic(EM) cytochemical technique. The ultrathin cryosections of rapid frozen fresh rat auricles were used for measuring Ca concentration with a JEM1200EX electron microscope equipped with a Link AN 10000 energy dispersive X-ray spectroscope. The measurement showed that the Ca concentration in the ASG was quite high, being 81 ±15 mmol/kg(n=10), comparable with that found in the sarcoplasmic reticulum. With the Ca2+-ATPase EM cytochemical technique, the reaction products proved to be deposited on the membrane of the ASG. It was postulated that the Ca2+-ATPase on the membrane of ASG pumped Ca2+ out of the cytosol into the ASG and thus maintained a high Ca concentration inside the ASG. Therefore, the ASG might be considered to be a Ca store in atrial cadiocytes.

关 键 词：心房特殊颗粒 细胞内钙库 心房 

分 类 号：R331.31[医药卫生—人体生理学]