人心房肌细胞胞嘧啶单核苷酸酶细胞化学与心钠素免疫电镜研究

CMPase CYTOCHEMICAL AND ANF IMMUNOCYTOCHEMICAL OBSERVATION ON THE ATRIAL MUSCLE CELLS OF HUMAN

本研究应用电镜酶细胞化学法和免疫电镜胶体金技术,对人心房肌细胞中的胞嘧啶单核苷酸酶(CMP酶)和心钠素进行了定位和定量研究。心钠素定位于心房特殊颗粒,数量较多,大小均一,直径0.20±0.05μm,分布于整个胞浆中,多聚集成群,尤以肌膜下和核极区较多见。而CMP酶存在于初级溶酶体中,溶酶体大小不一,直径0.30±0.19μm,显著大于心房特殊颗粒(P<0.001),一般在核极区成群分布,也单个散在于肌原纤维之间和肌膜下。常见心房特殊颗粒与初级溶酶体邻近,偶见二者相接触,少数心房特殊颗粒的单位膜上出现CMP酶反应产物。提示初级溶酶体可能参与前心房肽的转化和心钠素释放的调节。

The human atrial muscle cells were investigated by ultrastructural CMPase cytochemistry and atrial natriuretic factor (ANF) immunocytochemistry. The primary lysosomes and ANF were labelled by these techniques, respectively. ANF was localized in the atrial specific granules, these granules were similar in size and 0.20± 0.051μm in diameter, distributed over the entire cytoplasm, preferentially being located in the subsarcolemmal and perinuclear region and forming clusters. Primary lysosomes were various in size, 0.30±0.191μm in diameter, significantly larger than atrial specific granules (P<0.001), which usually formed clusters in the perinuclear region and interspersed in cytoplasm. Our study showed that primary lysosomes were 3.77±0.07 less numerous than the atrial specific granules in number. Some atrial specific granules were observed to be apposed to the primary lysosomes frequently and some of these grantiles were observed to be fused with the primary lysosomes. Simultaneously, some atrial specific granules showed CMPase reaction product on their unit membrane. The results of present study indicated that the atrial specific granules and primary lysosomes were the main cytoplasmic granules in human atrial myocytes. They were different in size and intracellular location. The lysosomes of atrial myocytes were possibly involved in converting to the active peptide from pro-ANF as well as regulating the secretion of ANF.