Enzyme histochemical localization of Na+,K+-ATPase and NADH-DE in the developing rat parotid gland

Abstract

Information on ductal differentiation in the developing rat parotid gland is sparse. Striated and excretory ducts are rich in a number of enzymes related to ion movement. The objective of this investigation was to delineate histochemically the chronology of two of these, ouabain-sensitive Na(+),K(+)-ATPase and NADH-DE, in the developing rat parotid gland. Parotid glands were excised from rats at representative ages from 20 days in utero to 42 days. Enzyme histochemistry was performed on air-dried frozen sections. For Na(+), K(+)-ATPase, some sections also were fixed in phosphate-buffered formalin. Ouabain blocked Na(+),K(+)-ATPase activity, and neither enzyme reacted without substrate. Weak Na(+),K(+)-ATPase reactions were initially seen in unfixed sections at 1 day, and increased steadily to the adult pattern of strong (concentrated basolaterally) in striated ducts and excretory ducts, respectively, and weak to modest (diffuse) in acini and intercalated ducts at 28 days. In fixed sections, localization was sharper but the reaction was somewhat reduced. NADH-DE was modest in terminal buds and ducts before birth, then progressively changed to the adult pattern of weak in acini and intercalated ducts and strong (concentrated basally and luminally) in striated and excretory ducts at 28 days. As demonstrated by enzyme histochemistry of Na(+),K(+)-ATPase and NADH-DE, differentiation of rat parotid striated ducts and excretory ducts occurs mainly between birth and 28 days. Anat Rec 256:72-77, 1999. Published 1999 Wiley-Liss, Inc.

Interlobular excretory ducts of mammalian salivary glands: Structural and histochemical review

“…By comparing the two samples, it is apparent that there is a net resorption of electrolytes as the saliva passes through the duct system. The presence of Na ϩ ,K ϩ -ATPase at the base of ED cells in human, feline, and rodent salivary glands provides the enzymatic basis for such activity (Winston et al, 1988(Winston et al, , 1990Peagler and Redman, 1999). The physiological events involved in this process have been reviewed in detail by Schneyer et al (1972), Martinez (1987), and Young et al (1987).…”

“…1990; Garrett et al, 1992), in human parotid, sublingual, and submandibular glands (Winston et al, 1988), in mouse parotid and sublingual glands (Winston et al, 1988), in mouse submandibular glands (Sims-Sampson et al, 1984;Winston et al, 1988;Kurihara et al, 1996), and in the rat parotid, sublingual, and submandibular glands (Winston et al, 1988). Na ϩ ,K ϩ -ATPase has been studied in the ED cells of the postnatally developing rat parotid gland (Peagler and Redman, 1999). Another ATPase has been localized primarily on the microvilli of ED cells of the rat parotid and submandibular glands; this is an ecto-ATPase and may be identical to a membrane glycoprotein called C-CAM 105 (Murphy et al, 1994).…”

Altered Expression of Sodium Transporters and Water Channels in the Submandibular Gland of Rats Treated with Nitric Oxide Synthesis Inhibitors

“…Na + ,K + -ATPase produces an inward-directed sodium chemical gradient in the acinar cell2). Although sodium influx is negligible in resting cells, it is rapidly increased by activation of NKCC2, NHE1, and nonselective cation channels in the acinar cell3).…”