ABSTRACT
Mammalian salivary glands are known to produce a number of biologically active peptides. The aim of this study was to extend our previous results showing the presence of a biologically active insulin-like immunoreactive peptide in rat salivary glands. In rodents, where two nonallelic and functional insulin genes are expressed, the co-expression of both genes seems to be limited to beta-cells of pancreatic islets or to embryologic developmental processes. We have investigated the expression of insulin genes in rat submandibular glands and in a murine immortalized submandibular cell line, SCA-9. For this purpose, total RNAs were isolated and submitted to reverse transcription. The cDNAs obtained were amplified by a nested polymerase chain reaction using rat preproinsulin I and II primers. Our data show that both preproinsulin I and II mRNAs are expressed in adult rat submandibular glands as well as in the SCA-9 cell line. The identification of salivary gland rat preproinsulin I and II was confirmed by direct sequencing. These results provide, for the first time, evidence for the expression of both preproinsulin I and II mRNA in an extra-pancreatic tissue from adult rodents.
Subject(s)
Proinsulin/biosynthesis , Protein Precursors/biosynthesis , Submandibular Gland/metabolism , Animals , Base Sequence , Cell Line , Gene Expression , Insulin , Male , Mice , Molecular Sequence Data , Polymerase Chain Reaction , Proinsulin/genetics , Protein Precursors/genetics , RNA, Messenger/analysis , Rats , Rats, Wistar , Sequence Analysis, DNAABSTRACT
Intracellular pH (pHi) and several ion transport mechanisms in cultured murine salivary gland cells (SCA-9) were studied using a videomicrofluorometric method and the H+-specific probe C-SNARF-1. The aim of this study was to test SCA-9 cells' pHi regulation mechanisms and evaluate if this cell line is representative of submandibular gland cells. Resting pHi in unstimulated cells was estimated to be 7.17+/-0.07. To investigate the presence of Na+/H+ and Cl-/HCO3- antiports as well as Na+/K+/2Cl- symports in SCA-9 cells, we used different specific blockers, dimethyl-amiloride, disulfonic stilbene, bumetanide and furosemide. In order to study SCA-9 cell capacity to regulate their pHi in response to alkaline and acid loads, we applied the NH4Cl prepulse method to all these blockers. The results showed that SCA-9 cells possess both antiports and symports involved in pHi regulation, and that this cell line can be used as a convenient model to study pHi regulatory mechanisms in salivary cells.
Subject(s)
Hydrogen/metabolism , Ion Transport , Submandibular Gland/cytology , Submandibular Gland/metabolism , Acid-Base Equilibrium , Ammonium Chloride , Animals , Antiporters/antagonists & inhibitors , Antiporters/metabolism , Biological Transport, Active , Carrier Proteins/antagonists & inhibitors , Carrier Proteins/metabolism , Chloride-Bicarbonate Antiporters , Fluorometry , Hydrogen-Ion Concentration , Intracellular Membranes/metabolism , Mice , Microscopy, Video , Models, Biological , Sodium-Hydrogen Exchangers/antagonists & inhibitors , Sodium-Hydrogen Exchangers/metabolism , Sodium-Potassium-Chloride Symporters , Tumor Cells, CulturedABSTRACT
The purpose of this study is to show the effects of dental occlusion on postural position. Thirty subjects were divided into two groups: an experimental group who wore mandibular orthopedic repositioning appliances (MORA) and a control group who wore no oral device. All of the subjects underwent the same Fukuda-Unterberger experimental stepping test to check their postural attitude. Any deviation of the subject during the test from his initial position was analyzed. The results seemed to confirm that altering dental occlusion by wearing an oral appliance could induce some fluctuations in dynamic postural attitude. The phenomenon occurs after prolonged wearing of a MORA. Feedback effects are gradual after removing the mandibular splint.
