Pannexins are channel proteins displaying functional similarities to gap junctions in vertebrates and are regarded as transmembrane ATP-releasing channels. A member of this family, denominate pannexin1, has been detected in the epidermis and cutaneous adnexal structures. Here we used immunohistochemistry to investigate whether human digital Merkel cells express this protein since ATP is postulated as a neurotransmitter in the Merkel cell-axon complexes low-threshold mecahoreceptors. Pannexin1 immunoreactivity was found in cytokeratine 20-, chromogranin A- and synaptophysin-positive cells placed at the basal layer of the epidermis. Cell displaying pannexin1 immunoreactivities were thus identified as Merkel cells and showed close contact with nerve profiles. Light pannexin1 immunoreactivity in dermal blood vessels was also verified. Present results demonstrate for the first time the expression of pannexin1 in human digital Merkel cells supporting the idea that ATP can be involved directly or indirectly in the mechanotransductional process at Merkel-axon complexes.

Pannexins 是通道蛋白，与脊椎动物的间隙连接具有相似的功能，被认为是跨膜 ATP 释放通道。该家族的一个成员，命名为 pannexin1，已在表皮和皮肤附件结构中检测到。在这里，我们使用免疫组织化学来研究人类数字默克尔细胞是否表达这种蛋白质，因为 ATP 被假定为默克尔细胞-轴突复合物低阈值 mecahoreceptors 中的神经递质。在位于表皮基底层的细胞角蛋白 20、嗜铬粒蛋白 A 和突触素阳性细胞中发现了 Pannexin1 免疫反应性。因此，显示 pannexin1 免疫反应性的细胞被鉴定为默克尔细胞，并显示出与神经分布密切接触。还验证了真皮血管中的轻 pannexin1 免疫反应性。