English K B, Burgess P R, Kavka-Van Norman D
J Comp Neurol. 1980 Nov 15;194(2):475-96. doi: 10.1002/cne.901940212.
The ultrastructure of Merkel cells and cutaneous nerves was examined in fetal, newborn, and 7-day-old rats. The earliest observation of cells having some, but not all, of the features of mature Merkel cells was at 16 days gestation in snout skin. These early presumptive Merkel cells resembled the neighboring keratocytes, except that they contained dense-cored vesicles scattered in the cytoplasm. Presumptive Merkel cells were seen only in the epidermis, although a careful search was made of the dermis. Developing neurons were not observed to penetrate the epidermal basal lamina when presumptive Merkel cells were first seen. The earliest observation of identifiable nerve axons in the snout epidermis was at 17-171/2 days gestation. Study of the presumptive Merkel cells through successively older gestational stages showed that the cells became innervated and progressively developed the characteristics of adult Merkel cells. We suggest that Merkel cells arise from keratocyte-like precursors in rat epidermis, at a time when skin nerves may still be several micrometers away.
在胎儿、新生大鼠和7日龄大鼠中检查了默克尔细胞和皮肤神经的超微结构。最早观察到具有一些但并非全部成熟默克尔细胞特征的细胞是在妊娠16天时的口鼻部皮肤中。这些早期的推测性默克尔细胞类似于相邻的角质形成细胞，只是它们的细胞质中散在分布着有致密核心的小泡。尽管对真皮进行了仔细搜索，但推测性默克尔细胞仅见于表皮。当首次观察到推测性默克尔细胞时，未观察到发育中的神经元穿透表皮基膜。最早在妊娠17 - 17.5天时在口鼻部表皮中观察到可识别的神经轴突。对不同妊娠阶段的推测性默克尔细胞进行研究表明，这些细胞开始接受神经支配，并逐渐发展出成年默克尔细胞的特征。我们认为，在大鼠表皮中，默克尔细胞起源于角质形成细胞样前体细胞，此时皮肤神经可能仍在几微米之外。
