Vol 49, No 3 (2011)
Original paper
Published online: 2011-10-28
Immunodetection of aquaporin 5 in sheep salivary glands related to pasture vegetative cycle
DOI: 10.5603/FHC.2011.0065
Folia Histochem Cytobiol 2011;49(3):458-464.
Abstract
Mammalian aquaporins (AQPs) are a family of at least 13 integral membrane proteins expressed in
various epithelia, where they function as channels to permeate water and small solutes. AQP5 is widely expressed
in the exocrine gland where it is likely involved in providing an appropriate amount of fluid to be
secreted with granular contents. As regards AQP5 expression in the salivary glands, literature is lacking concerning
domestic animal species. This study was chiefly aimed at immunohistochemically investigating the presence
and localization of AQP5 in sheep mandibular and parotid glands. In addition, AQP5 immunoreactivity
was comparatively evaluated in animals fed with forage containing different amounts of water related to the
pasture vegetative cycle, in order to shed light on the possible response of the gland to environmental modifications.
Moderate AQP5-immunoreactivity was shown at the level of the lateral surface of mandibular serous
demilune cells, not affected by the pasture vegetative cycle or water content. On the contrary, the parotid gland
arcinar cells showed AQP5-immunoreactivity at the level of apical and lateral plasma membrane, which was
slight to very strong, according to the pasture vegetative development and interannual climatic variations. AQP5
expression is likely due to its involvement in providing appropriate saliva fluidity. Indeed, the lowest AQP5
immunoreactivity was noticed when food water content increased. (Folia Histochemica et Cytobiologica 2011;
Vol. 49, No. 3, pp. 458–464)
Keywords: AQP5sheepsalivary glandspasture vegetative cycleimmunohistochemistry
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