Studies on structure and function of gastropod epithelia have been www.selleckchem.com/products/Rapamycin.html performed regarding the epithelium of specialized organs such as mantle [3�C5], tentacles [6], and defensive glands [7]. Regarding the gastropod foot some research has focused on histological studies in muscular [8�C11] and connective tissues [12]. However, although the epithelium of the foot has received much more attention [13�C18], histochemical and ultrarstructural studies on the vestigatropod pedal epithelium are scarce [19, 20].Typically the gastropod foot is covered by a mucus layer important to a range of functions including lubrication, locomotion, protection, and adhesion to the substrate [21]. It has been showed the viscoelastic properties of limpet mucus can be modified in different ways when a specific function is required [22, 23].

Moreover, the mucus layer has an important ecological role in the community behavior [24] and in the ecosystem, as defense or attraction. It also provides a habitat for microorganisms as it has been described in Haliotis diversicolor [25].The mucus layer covering the gastropods foot is produced by epithelial secretory cells and subepithelial glands. The diversity of these cell types, their composition, and distribution vary from species to species. For instance Grenon and Walker [14] distinguished nine types of secretory cells in the foot epithelium of the marine gastropod, Patella vulgata, but a different distribution of secretory cells has been found by the same authors in another limpet Acmaea tessulata.

However Shirbhate and Cook [18] described ten secretory AV-951 cell types in another marine gastropod Littorina littorea. The conventional histochemical methods used in these studies revealed different types of secretory cells containing acidic and neutral glycoconjugates, but they yield incomplete information on the structural details of glycans. The presence of glycosaminoglycans and glycoprotein has been demonstrated, by using lectins, in the epithelium of a few mollusks [26, 27], but no data exist in the literature on the nature and distribution of glycoconjugates in the foot of the Haliotis species.In addition to the secretory system, gastropods have been described as containing a variety of pigments in their epithelial cells, including carotenoid, melanin, and bilichromes among others [28]. In a previous study by using light microscopy, Bravo et al. [29] have characterized two types of pigmented cells located in the crests and grooves of the unfolded side foot of Haliotis tuberculata (Linnaeus, 1758).