Brown M R, Raikhel A S, Lea A O
Tissue Cell. 1985;17(5):709-21. doi: 10.1016/0040-8166(85)90006-0.
The ultrastructure of endocrine cells in the midgut of the adult mosquito, Aedes aegypti, resembled that of endocrine cells in the vertebrate gastro-intestinal tract. Midgut endocrine cells, positioned basally in the epithelium as single cells, were cone-shaped and smaller than the columnar digestive cells. The most distinctive characteristic of endocrine cells was numerous round secretory granules along the lateral and basal plasma membranes where contents of the granules were released by exocytosis. Secretory granules in each individual cell were exclusively of one type, either solid or 'haloed', and for all cells observed, the range in granule diameter was 60-120 nm. The cytoplasm varied in density from clear to dark. Lamellar bodies were prominent in the apical and lateral cellular regions and did not exhibit acid phosphatase activity. The basal plasma membrane was smooth adjacent to the basal lamina, whereas in digestive cells the membrane formed a labyrinth. Some endocrine cells reached the midgut lumen and were capped by microvilli; a system of vesicles and tubules extended from beneath the microvilli to the cell body. An estimated 500 endocrine cells were distributed in both the thoracic and abdominal regions of the adult midgut. In one midgut, we classified a sample of endocrine cells according to cytoplasmic density and granule type and size; endocrine cells with certain types of granules had specific distributions within the midgut.
成年埃及伊蚊中肠内分泌细胞的超微结构与脊椎动物胃肠道内分泌细胞的超微结构相似。中肠内分泌细胞作为单个细胞位于上皮基部，呈锥形，比柱状消化细胞小。内分泌细胞最显著的特征是沿着外侧和基部质膜有许多圆形分泌颗粒，颗粒内容物通过胞吐作用释放。每个细胞中的分泌颗粒仅为一种类型，要么是实心的，要么是“有晕的”，在所有观察到的细胞中，颗粒直径范围为60-120纳米。细胞质密度从透明到深色不等。板层小体在细胞顶端和外侧区域突出，不表现出酸性磷酸酶活性。基部质膜与基膜相邻处光滑，而在消化细胞中，膜形成迷路。一些内分泌细胞延伸至中肠腔，顶端有微绒毛；一个由小泡和小管组成的系统从微绒毛下方延伸至细胞体。估计有500个内分泌细胞分布在成年中肠的胸部和腹部区域。在一个中肠中，我们根据细胞质密度以及颗粒类型和大小对内分泌细胞样本进行了分类；具有某些类型颗粒的内分泌细胞在中肠内有特定的分布。
