In our current work,in vivoexamination of AQP5 distribution in labial salivary glands following stimulation of secretion has been carried out in normal individuals and in patients with Sjögren's syndrome.SUBJECTS AND METHODS:
For this study, we selected five patients with primary Sjögren's syndrome (mean age 62.4 ± 10.6 s.d. years) diagnosed in accordance with the European Cooperative Community classification criteria. There were five patients (mean age 27 ± 2.5 s.d. years) in the control group. The subcellular distribution of AQP5 in human labial gland biopsies was determined with light and immunoelectron microscopy before and 30 min after administration of oral pilocarpine.RESULTS:
In unstimulated control and Sjögren's labial glands, AQP5 is about 90% localized in the apical plasma membrane, with only rarely associated gold particles with intracellular membrane structures. We have found no evidence of pilocarpine-induced changes in localization of AQP5 in either healthy individuals or patients with Sjögren's syndrome.CONCLUSIONS:
Our studies indicate that neither Sjögren's syndrome itself, nor muscarinic cholinergic stimulationin vivocaused any significant changes in the distribution of AQP5 in the labial salivary gland cells.