Original scientific paper
https://doi.org/10.15644/asc57/3/8
The Role of Uroguanylin in Regulation of Ion Transport in Salivary Glands
Domagoj Jakovac
; Department of Physiology, School of Dental Medicine, University of Zagreb, Croatia
Martina Ratko
; Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Croatia
Iva Marolt Banek
; Department of Physiology, School of Dental Medicine, University of Zagreb, Croatia
Ivana Lapić
; Department of Laboratory Diagnostics, University Hospital Centre Zagreb, Zagreb, Croatia
Aleksandra Dugandžić
; Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Croatia; Department of Physiology, School of Medicine, University of Zagreb, Croatia
Abstract
Objective of work: Guanylin peptides are considered to be the only intrinsic regulators of salivary glands secretion. Therefore, the aim of this study is to determine the effects of systemic uroguanylin (UGN) of the salivary flow and ion composition as well as if those effects include activation of guanylate cyclase C (GC-C). Materials and Methods: This study was conducted on 7 months old C57Bl6NCrl (wild type, WT) and GC-C knockout (KO) mice. Salivary flow rate and ion composition were determined after pilocarpine stimulation with UGN (30 µg/animal) or saline i.p. application. The expression of mRNA for AQPs, NHEs, NBCn1, Slc26a3/a6 and CFTR were determined by qPCR in submandibular salivary glands. Results: When applied i.p., UGN decreases the pilocarpine stimulated saliva flow rate and increased concentration of Na + , H + and Cl -. In GC-C KO mice, UGN shows no effect on saliva flow rate, while the concentrations of Na + , H + and Cl -are the same in GC-C KO littermates when compared to WT mice. UGN increased expression of Slc26a6 while in GC-C KO mice Slc26a6 had a higher expression when compared to WT mice, suggesting involvement of GC-C independent signalling pathway for UGN. The difference in Slc26a6 in GC-C KO mice is not unique for salivary glands because it was found also in duodenum and kidney cortex. Conclusions: The effects of UGN via basolateral membrane of salivary glands cells have not been considered up to date. In our study, UGN, when applied i.p., decreased salivary flow rate, pH, and changed composition of other ions. Therefore, plasma UGN an hour after a meal could have physiological and pathological importance (development of cavities, inflammations or demineralisations) and inhibition of systemic UGN effects could be consider as a new approach in treatment of those conditions.
Keywords
Submandibular Gland; Enterotoxin Receptors; Salivation; Pilocarpine; GC-C Independent Signaling Pathway; Stimulated Saliva Production; Saliva Flow Rate; pH; qPCR
Hrčak ID:
308212
URI
Publication date:
27.9.2023.
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