Differential Expression and Cellular Localization of Na+-K+-ATPase Isoforms in Rat Salivary Gland / 대한해부학회지

ABSTRACT

It is the existence of a polarized distribution of ion transporters and channels which is thought to underlie the vectorial salt movement. The present study was performed to examine the expression and polarized distribution of Na+-K+-ATPase isoforms believed to be essential for salivary secretion in the rat salivary gland using immunohis-tochemistry. Na+-K+-ATPase alpha1 subunit immunoreactivity was prominent in the granular convoluted duct of the submandibular gland, and striated and excretory duct of three major salivary glands. The submandibular ganglion and postganglionic nerve fiber exhibited moderate immunoreactivity, whereas the intercalated duct and acinar cells of major salivary gland were weakly labeled. Na+-K+-ATPase beta1 subunit immunoreactivity was prominent in the granular convoluted duct of the submandibular gland, intercalated duct of the sublingual gland, acinar cells of the parotid gland, and striated and excretory ducts of major salivary gland. The submandibular ganglion, intercalated duct of the submandibular gland, and acinar cells of the sublingual gland exhibited moderate immunoreactivity, whereas acinar cells of the submandibular gland and intercalated duct of the parotid gland were weakly labeled. In these segments, alpha1 and beta1 immunoreactivity was expressed at the basolateral pole, and no apical expression was detected. These results suggest that major salivary glands are comprised of at least two structurally unique Na+-K+-ATPase isoforms, which are participated in primary saliva formation and transport.