Effects of pentagastrin on human parotid salivary glands

LOY, FRANCESCO;DIANA M;EKSTRÖM J;RIVA A.

2008-01-01

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Abstract

Previous studies report that salivary glands activity can be influenced by gastrointestinal hormones. Aras and Ekström (2006) demonstrated that intravenous infusion of pentagastrin causes, in rat parotid, protein secretion without fluid production. Aim of the present study is that of testing the effect of pentagastrin in human salivary glands in vitro. Samples of human normal parotid glands obtained at surgery, were immersed in an oxygenated inorganic medium and treated according to the procedure described in our previous works (Riva et al., 2002; Testa Riva et al., 2006). Following treatment, the medium was analyzed by the Lowry method in order to determine its amylase and protein content (Aras and Ekström, 2006). Tissue samples were then treated by our modification of the HRSEM osmium maceration technique (Riva et al., 1998), that by removing all cytoplasmic organelles, exposes the surfaces of the plasmalemma involved in exocytosis. Since protein secretion occurs by the latter process, we calculate the density of microvilli and that of microbuds per µm2 of the cytoplasmic surface of the luminal membrane (Testa Riva et al., 2006). Stimulation was performed by adding pentagastrin (130 µM, 65 µM, 26 µM) to the medium for about 15 min. For comparison, other samples were treated, in the same way, with the pan muscarinic agent carbachol (10 µM). Our results confirm that pentagastrin does act on secretory cells of human parotid glands and that there is a protein secretion. Furthermore findings obtained by pentagastrin will be compared and discussed with those produced by carbachol.