UMR, Université Montpellier II, France.
Cell Tissue Res. 2010 Mar;339(3):543-50. doi: 10.1007/s00441-009-0911-x.
Because of the permeability of the chorion, sea bass embryos are exposed to seawater before hatching and hence require precocious osmoregulatory processes. Several studies of other species have demonstrated the existence of ion-transporting cells located on the yolk sac membrane of embryos. In these cells, called ionocytes, ion movements are controlled by a pool of transmembrane proteins. Among them, the Na(+)/K(+)-ATPase, an abundant driving enzyme, has been used to reveal the presence or absence of ionocytes. We have immunostained the Na(+)/K(+)-ATPase in sea-bass embryos and shown the presence of the first ionocytes on the yolk sac membrane at stage 12 somites and the occurrence of ionocytes at other sites before hatching. Ionocytes located on the first gill slits have been identified at stage 14 somites. Primitive enteric ionocytes have also been detected at stage 14 somites in the mid and posterior gut. The presence of these cells might be related to the early opening of the gut to perivitelline fluids, both anteriorly by the gill slits and posteriorly by the anus. The role of embryonic ionocytes in osmoregulation before hatching is discussed.
由于卵膜的通透性，鲈鱼胚胎在孵化前就会接触到海水，因此需要早熟的渗透调节过程。其他物种的几项研究表明，胚胎的卵黄囊膜上存在着离子转运细胞。在这些被称为离子细胞的细胞中，离子运动由跨膜蛋白池控制。其中，Na(+)/K(+)-ATPase 是一种丰富的驱动酶，被用来揭示离子细胞的存在与否。我们已经在鲈鱼胚胎中对 Na(+)/K(+)-ATPase 进行了免疫染色，并在 12 体节阶段的卵黄囊膜上发现了第一批离子细胞，并在孵化前的其他部位发现了离子细胞。在 14 体节阶段，我们已经在第一鳃裂上发现了离子细胞。在中肠和后肠的 14 体节阶段，也检测到了原始肠离子细胞。这些细胞的存在可能与肠道早期对卵黄液的开放有关，前部通过鳃裂，后部通过肛门。讨论了孵化前胚胎离子细胞在渗透调节中的作用。
