Localization of calbindin D28K-like immunoreactivity in fish gill: a light microscopic and immunoelectron histochemical study

Abstract

SummaryThe presence of calbindin D28K in fish (Heteropneustes fossilis) gill was studied by use of specific antibodies raised against chick duodenal 28 kD a calbindin in immunoperoxidase and electron-microscopic labelling experiments. Immunoreactivity for calbindin D28K, which has been observed in the intestine of a number of avian and mammalian species, is reported for the first time in the gill. It was primarily located in neuroendocrine (NE) cells. Some immunoreactivity was also located in the glycocalyx of the non-endocrine cells, i.e., the pavement cells, which have ultrastructural characteristics quite different from those of endocrine cells.The calbindin-immunopositive NE cells were ascertained in both gill filamental and lamellar epithelium. All the NE cells contained secretory granules as the most distinc tive feature of these cells. Ultrastructurally, two types of NE cells were distinguished according to the morphology of their secretory granules.The calbindin immunoreactivity in the NE cells was stimulated when the calcium concentration of the ambient water was rcduccd. The present findings suggest that NE

Distribution patterns of the paraneuronal endocrine cells in the skin, gills and the airways of fishes as determined by immunohistochemical and histological methods

“…Furthermore, the cells that are located in the gill area nearest to the chloride cells might influence the physiological state of these cells in a paracrine way. Calbindin DK28, calmodulin and S-100 protein are now considered novel markers of neuro-endocrine cells of teleost gill; these may be functionally related to the calcium modulated cellular processes in the gills (Zaccone et al, 1992b;Fasulo et al, 1993b).…”

“…Calmodulin is also located in fish epidermal and amphibian dermal mucous glands and the basal cell layers in the skin of terrestrial vertebrates (Wollina et al, 1991;Wollina, 1993). Calbindin DK28 and parvalbumin are found by immunohistochemistry in the surface cells of the gill epithelium and the glycocalyx of these (Zaccone et al, 1992b;Fasulo et al unpublished data). Calbindin and calmodulin are also reported as neuro-endocrine markers of gill neuro-endocrine cells (see below).…”

“…The precise function of calcium-binding proteins in fish epithelia is not known. It is argued for their involvement in the regulation of epithelial permeability to ions and water (Zaccone et al, 1989b(Zaccone et al, , 1992bWollina et al, 1991;Wollina, 1993).…”

“…Serotonin was detected in cells of the branchial epithelium, in both teleost and selachian species (Dunel-Erb et al, 1982). More recent ultrastructural and immunohistochemical evidence led to the discovery of receptosecretory cells within both the filamental and lamellar epithelium (Bailly et al, 1992;Zaccone et al, 1992b). In all the species examined the neuroendocrine cells occur singly or in small groups; they are more numerous in trout, eel, Ictalurus and Heteropneustes fossilis, than in Blennius sanguinolentus or the dipnoan Protopterus annectens.…”

“…In the catfish Heteropneustes fossilis, open neuro-endocrine cells in both lamellar and filamental epithelia of the gills react to antibodies against calbindin DK28 (Zaccone et al, 1992b) and calmodulin (Fasulo et aI., 1993b) as shown in Figs 16 and 17. In higher vertebrates calbindin is involved in calcium metabolism, the Ca ~+ uptake and transport (Wassermann & Fullmer, 1982); we speculate that in fish gills calcium signals could be transmitted to chloride cells that are concerned in uptake of calcium in flesh water.…”