Barrio Asensio, María Del CarmenMurillo González, Jorge AlfonsoPeña Melián, ÁngelPuerta Fonollá, Javier2023-06-202023-06-20Received:1999-10Barrio Asensio, M. C., Murillo González, J. A., Peña Melián, Á., Puerta Fonollá, J. «Immunocytochemical Study on the Triple Origin of the Sphincter Iris in the Chick Embryo». Development Genes and Evolution, vol. 209, n.o 10, octubre de 1999, pp. 620-24. Springer Link, https://doi.org/10.1007/s004270050296.0949-944X10.1007/s004270050296https://hdl.handle.net/20.500.14352/60010The ontogenic development of the sphincter iris has been studied by immunocytochemistry and standard staining on chick embryos from stage 25 HH to the time of hatching. We have used the monoclonal antibody 13F4, a highly specific marker of muscular cells. We have observed three different regions in the iris. Tn the pupillary region, immunoreactive cells are in continuous contact with the inner epithelium of the pupillary margin. In the intermediate region, the outer epithelium forms buds of pigmented cells that emigrate toward the stroma. In this epithelium cells that are totally or partially unpigmented exist, and they are 13F4 positive. In the sphincter we have observed 13F4 positive cells with melanin granules. In the ciliary region, the immunoreactivity appears in dispersed mesenchymal cells. The present findings are consistent with a triple origin of the sphincter iris in the chick embryo. This muscle is derived from the inner epithelium of the pupillary margin, the intermediate region of the outer epithelium, and from the mesenchymal cells. The cells of the inner epithelium of the pupillary margin are differentiated into smooth muscle cells, and the remaining cells form striated muscle cells.engjournal articlehttp://dx.doi.org/10.1007/s004270050296http://link.springer.com/article/10.1007/s004270050296restricted access617.721611.842sphincter irischick embryoiris developmentmonoclonal antibody 13F4AnatomíaOftalmología2410.02 Anatomía Humana3201.09 Oftalmología