Elsevier

Tissue and Cell

Volume 46, Issue 1, February 2014, Pages 9-14
Tissue and Cell

Short communication
Serous goblet cells: The protein secreting cells in the oral cavity of a catfish, Rita rita (Hamilton, 1822) (Bagridae, Siluriformes)

https://doi.org/10.1016/j.tice.2013.08.001Get rights and content

Abstract

Serous goblet cells in the oral epithelium of Rita rita are characterized by the presence of distinct eosinophilic granules occupying large parts of the cytoplasm. In R. rita, a range of histochemical results reveal that these cells are involved in proteinaceous secretions, and thus likely contribute to various functions analogous to those of mammalian saliva. The secretions of these cells have also been associated with specific functions and are discussed in relation to their physiological importance with special reference to their roles in lubrication, alteration in viscosity, various functions of mucus such as handling, maneuvering and driving of food items toward the esophagus, maintaining taste sensitivity and protection of the oral epithelium. In addition, the serous goblet cells may also be considered as the primary defensive cell of the oral epithelium of R. rita. The results significantly add to very limited set of literature on the serous goblet cells and provide noteworthy information on the mucous secretions in the oral cavity of fish.

Introduction

Unquestionably, mucus, in the oral cavity of fish, is predominantly secreted by the mucous goblet cells (Sibbing et al., 1986, Sibbing, 1988, Sanderson et al., 1991, Sanderson et al., 1998, Yashpal et al., 2007) and is involved in diverse roles such as trapping of food particles, formation of food bolus, solubilization of food materials, facilitation of mastication, initial digestion of starches and lipids, lubrication and protection of epithelial surfaces, cleansing the oral cavity and antimicrobial activity as well (Domeneghini et al., 2005, Yashpal et al., 2007, Yashpal et al., 2009).

In teleost, the secretions elaborated by the cells, which are mainly characterized by the presence of distinct eosinophilic granules occupying large parts of the cytoplasm also contribute to the surface mucus. These ‘granular’ cells, involved in proteinaceous rather than mucoid secretions, were first described and designated as “serous goblet cells” by Whitear (1986).

Apart from the reports of serous goblet cells (SGCs) present in the skin epidermis (Whitear, 1986) and gill epithelium (Kumari et al., 2009) of several fish species, we are aware of only one published study reporting the presence of these cells in the oral cavity of Rita rita, namely that of Yashpal et al. (2007). While describing the histochemical characterization of glycoproteins, Yashpal et al. (2007) briefly mentioned SGCs and considered them as one of the important constituents of the secretory elements in the epithelium at different regions of the oral cavity of R. rita. Therefore, in order to elucidate the functional role of this cell type, the present communication describes the histology and histochemistry of SGCs in the oral cavity of the catfish, R. rita in relation to its habit and habitat.

R. rita Hamilton, 1822 (Bagridae, Siluriformes) is a sluggish, bottom dwelling carnivorous catfish and inhabits the rivers, canals, ponds, streams, backwater of quiet eddies and estuaries preferably muddy to clear water (Shrestha, 1990, Rahman, 2005, Yashpal et al., 2006, Yashpal et al., 2007, Mushahida-Al-Noor et al., 2013). In spite of its high commercial value and the potential to satisfy various tastes of consumers, the availability of R. rita is decreasing day by day due to environmental changes of the breeding ground and currently it is enlisted as a critically endangered fish species (Mollah et al., 2011).

Section snippets

Fish samples

Live specimens of R. rita (mean ± S.D., standard length, Ls, 105 ± 6 mm; n = 10), irrespective of their sex were collected from river Ganges, Varanasi, Uttar Pradesh, India and maintained in a laboratory aquarium with a layer of sand at the bottom for 24–48 h at 25 ± 2 °C. The fish were regularly fed with minced goat liver and sacrificed by exposure to ice cold water for an extended period of time (∼5 min) following Mittal and Whitear (1978). Immediately after the sacrifice, pieces of the roof and floor of

Results

The oral cavity, in R. rita, is distinguished into the dorsal roof and the ventral floor. The roof consists of the upper jaw, the velum, the palatine regions and the palate; and the floor consists of the lower jaw, the velum and the tongue (Yashpal et al., 2006). The velum, the palate and the tongue are edentulous. In contrast, the upper jaw, the palatine regions and the lower jaw are characteristically equipped with teeth (Yashpal et al., 2006). The stratified epithelium lining different

Discussion

The SGCs, with strong eosinophilic granular contents, are primarily involved in the elaboration of proteinaceous secretions, form one of important constituents of the secretory elements in the epithelium at different regions of the oral cavity of R. rita. A literature search revealed that the cells similar in appearance to SGCs (present study) have also been observed in the skin, gills and gut tissues of different fish species and have been described variously as “rodlet cells” (Weisel, 1971),

Acknowledgements

Madhu Yashpal was supported as a Project Associate under the Major Research Project No. F.3-131/2003 (SR) (Principal Investigator: Prof. A.K. Mittal) sanctioned by the University Grants Commission, Government of India.

References (46)

  • C.B. Basbaum et al.

    The serous cell

    Annu. Rev. Physiol.

    (1990)
  • N. Blackstock et al.

    Acidophilic granular cells in the epidermis of the brown trout (Salmo trutta L.)

    Cell Tissue Res.

    (1980)
  • G.A. Bubenik

    Localization, physiological significance and possible clinical implication of gastrointestinal melatonin

    Biol. Signals Recept.

    (2001)
  • C. Cirillo et al.

    Role of serotonin in gastrointestinal physiology and pathology

    Minerva Endocrinol.

    (2011)
  • P.G. de Almeida et al.

    Morphological re-evaluation of the parotoid glands of Bufo ictericus (Amphibia, Anura, Bufonidae)

    Contrib. Zool.

    (2007)
  • M.J. Evans et al.

    Role of nonciliated cells in renewal of the bronchial epithelium of rats exposed to NO2

    Am. J. Pathol.

    (1986)
  • E. Gisbert et al.

    Histochemistry of the development of the digestive system of Siberian sturgeon during early ontogeny

    J. Fish Biol.

    (1999)
  • Kapila et al.

    Diabetes and oral changes: the tryptophan metabolism link?

    J. Clin. Diagn. Res.

    (2012)
  • P. Li et al.

    New developments in fish amino acid nutrition: towards functional and environmentally oriented aquafeeds

    Amino Acids

    (2009)
  • C. Maake et al.

    Neurohormonal peptides, serotonin and nitric oxide synthase in the enteric nervous system and endocrine cells of the gastrointestinal tract of neotenic and thyroid hormone-treated axolotls (Ambystoma mexicanum)

    Cell Tissue Res.

    (1999)
  • A.K. Mittal et al.

    Histochemistry of the unicellular glands in relation to their physiological significance in the epidermis of Monopterus cuchia (Synbranchiformes, Pisces)

    J. Zool., Lond.

    (1977)
  • A.K. Mittal et al.

    Functional organisation of the skin of the green-puffer fish, Tetraodon fluviatilis (Ham. Buch.) (Tetraodontidae, Pisces)

    Zoomorphologie

    (1976)
  • A.K. Mittal et al.

    A note on cold anaesthesia of poikilotherms

    J. Fish Biol.

    (1978)
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    Present address: 9, Mani Nagar, Kandawa, Near Chitaipur Crossing, Varanasi 221 106, Uttar Pradesh, India.

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