• Molecules and Cells
• /
• v.26 no.6
• /
• pp.517-529
• /
• 2008

Porosomes are supramolecular, lipoprotein structures at the cell plasma membrane, where membrane-bound secretory vesicles transiently dock and fuse to release inravesicular contents to the outside during cell secretion. The mouth of the porosome opening to the outside, range in size from 150 nm in diameter in acinar cells of the exocrine pancreas, to 12 nm in neurons, which dilates during cell secretion, returning to its resting size following completion of the process. In the past decade, the composition of the porosome, its structure and dynamics at nm resolution and in real time, and its functional reconstitution into artificial lipid membrane, have all been elucidated. In this mini review, the discovery of the porosome, its structure, function, isolation, chemistry, and reconstitution into lipid membrane, the molecular mechanism of secretory vesicle swelling and fusion at the base of porosomes, and how this new information provides a paradigm shift in our understanding of cell secretion, is discussed.

• International Journal of Oral Biology
• /
• v.33 no.4
• /
• pp.143-147
• /
• 2008

The sodium bicarbonate cotransporter (NBC) protein is functionally expressed in salivary glands. In this experiment, we examined the role of NBC in $HCO_3^-$ formation in human parotid gland acinar cells. Intracellular pH (pHi) was measured in 2'-7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-loaded cells. Acetazolamide (0.1 mM) and 4,4'-diisothio cyanatostilbene-2,2'-disulphonic acid (DIDS, 0.5 mM) were used as specific inhibitors of carbonic anhydrase and NBC, respectively. The degree of inhibition was assessed by measuring the pHi recovery rate (${\Delta}pHi$/min) after cell acidification using an ammonium prepulse technique. In control experiments, ${\Delta}pHi$/min was $1.40{\pm}0.06$. Treatment of cells with 0.5 mM DIDS or 0.1 mM acetazolamide significantly reduced ${\Delta}pHi$/min to $1.14{\pm}0.14$ and $0.74{\pm}0.15$, respectively. Simultaneous application of DIDS and acetazolamide further reduced ${\Delta}pHi$/min to $0.47{\pm}0.10$. Therefore, DIDS and acetazolamide reduced ${\Delta}pHi$/min by 19% and 47%, respectively, while simultaneous application of both DIDS and acetazolamide caused a reduction in ${\Delta}pHi$/min of 67%. These results suggest that in addition to carbonic anhydrase, NBC also partially contributes to $HCO_3^-$ formation in human parotid gland acinar cells.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.1
• /
• pp.373-376
• /
• 2015

Background: EVA1A (eva-1 homolog A) is a novel gene that regulates programmed cell death through autophagy and apoptosis. Our objective was to investigate the expression profiles and potential role of EVA1A in normal and neoplastic human pancreatic tissues. Materials and Methods: The expression pattern of EVA1A in normal pancreatic tissue was examined by indirect immunofluorescence and confocal microscopy. Protein levels in paraffin-embedded specimens from normal and diseased pancreatic and matched non-tumor tissues were evaluated by immunohistochemistry. Results: EVA1A colocalized with glucagon but not with insulin, demonstrating production in islet alpha cells. Itwas strongly expressed in chronic pancreatitis, moderately or weakly expressed in the plasma membrane and cytoplasm in pancreatic acinar cell carcinoma, and absent in normal pancreatic acinar cells. Although the tissue architecture was deformed, EVA1A was absent in the alpha cells of pancreatic ductal adenocarcinomas, intraductal papillary mucinous neoplasms, mucinous cystadenomas, solid papillary tumors and pancreatic neuroendocrine tumors. Conclusions: EVA1A protein is specifically expressed in islet alpha cells, suggesting it may play an important role in regulating alpha-cell function. The ectopic expression of EVA1A in pancreatic neoplasms may contribute to their pathogenesis and warrants further investigation.

• Korean Journal of Veterinary Research
• /
• v.36 no.1
• /
• pp.1-9
• /
• 1996

Functional and morphological characteristics of the exocrine pancreas in genetic model BB rat of insulin dependent diabetes medllitus(IDDM) were carried out. Wistar rat was used as control animal. Flow rate of pancreatic juice, output of amylase and protein, and plasma glucose and insulin levess were examined. Also light and ultrastructural characteristics of the exocrine pancreas were observed. Pancreatic flow rate, output of amylase and protein, and insulin level were lower;glucose level was higher comparing with those of the control Wistar rat. In Wistar rat, exocrine pancreas was typical light microscopically. Zymogen granules and cell organelles were well developed in fine structure. Cell size of the periinsular acini was larger, and number of zymogen granules were more than those of the teleinsular acini. Most acinar cells were dark cells which containe well-developed RER in their cytoplasm. On the other hand, some light cells which have the dilated RER cisterns were found. In BB rat exocrine pancreas, cell size of per-and tele-insular acini similar to that of Wistar rat. The number of light cells occupied 40-50% compairing with that of Wistar rat. Zymogen granules were lower in number than that of Wistar rat and divied into three types in morphological characteristics ; type I showing normal structure, type II showing the wide hallo and small electron dense core in center of the zymogen granule and type III not having the electron dense core in the zymogen granule. The present ratio of type I, type II and type III are less than 5%, 30-40% and more than 50%, respectively.

• Applied Microscopy
• /
• v.12 no.2
• /
• pp.23-33
• /
• 1982

The parotid glands of squirrels(Tamias sibiricus asiaticus) were observed by the electron microscope. According to the characteristics of secretory granules and the morphology of cell organelles, the acinar cells could be distinguished into five types of cells(Type I , Type II, Type III, Type IV and Type V cell). Among these, Type III, Type IV and Type V cell were not identified up to date. The morphologic characteristics of the intercalated and striated ducts were the appearance of numerous long slender mitochondria which are located between the numerous basal infoldings, and the epithelium were consisted of light and dark cells. The desmosomes were also observed, and could not found the secretory granules in the cytoplasm of the both epithelium.

• International Journal of Oral Biology
• /
• v.31 no.4
• /
• pp.141-148
• /
• 2006

The effects of adenosine triphosphate(ATP) on salivary glands have been recognized since 1982. The presence of purinergic recepetors(P2Rs) that mediate the effects of ATP in various tissues, including parotid and submandibular salivary gland, has been supported by the cloning of receptor cDNAs and the expression of the receptor proteins. P2Rs have many subtypes, and the activation of these receptor subtypes increase intracellular $Ca^{2+}$, a key ion in the regulation of the secretion in the salivary gland. The apical pores of taste buds in circumvallate and foliate papillae are surrounded by the saliva from von Ebner salivary gland(vEG). Thus, it is important how the secretion of vEG is controlled. This study was designed to elucidate the roles of P2Rs on salivary secretion of vEG. Male Sprague-Dawley rats (about 200 g) were used for this experiment. vEG-rich tissues were obtained from dissecting $500-1,000\;{\mu}m$ thick posterior tongue slices under stereomicroscope view. P2Rs mRNA in vEG acinar cells were identified with RT-PCR. To observe the change in intracellular $Ca^{2+}$ activity, we employed $Ca^{2+}-ion$ specific fluorescence analysis with fura-2. Single acinar cells and cell clusters were isolated by a sequential trypsin/collagenase treatment and were loaded with $10\;{\mu}M$ fura -2 AM for 60 minutes at room temperature. Several agonists and antagonists were used to test a receptor specificity. RT-PCR revealed that the mRNAs of $P2X_4$, $P2Y_1$, $P2Y_2$ and $P2Y_3$ are expressed in vEG acinar cells. The intracellular calcium activity was increased in response to $10\;{\mu}M$ ATP, a P2Rs agonist, and 2-MeSATP, a $P2Y_1$ and $P2Y_2R$ agonist. However, $300\;{\mu}M\;{\alpha}{\beta}-MeATP$, a $P2X_1$ and $P2X_3R$ agonist, did not elicit the response. The responses elicited by $10\;{\mu}M$ ATP and UTP, a $P2Y_2R$ agonists, were maintained when extracellular calcium was removed. $10\;{\mu}M$ suramin, a P2XR antagonist, and reactive blue 2, a P2YR antagonist, partially blocked ATP-induced response. However, when extracellular calciums were removed, suramin did not abolish the responses elicited by ATP. These results suggest that P2Rs play an important role in salivary secretion of vEG acinar cells and the effects of ATP on vEG salivary secretion may be mediated by $P2X_4$, $P2Y_1$, $P2Y_2$, and/or $P2Y_3$.

• Asian-Australasian Journal of Animal Sciences
• /
• v.7 no.1
• /
• pp.103-112
• /
• 1994

This study was a sequential experiment consisting if feeding trial and in vitro culture studies. Feeding was conducted by $2{\times}2{\times}2$ factorial design with two cimaterol levels (0, 0.25 mg/kg), two energy levels (3,200, 2,900 ME kcal/kg) and two sexes. In starting period (0-21 days) broilers were fed diets containing two energy level without dietary supplementation of cimaterol. During finishing period (21-42 days) cimaterol groups were fed cimaterol supplemented diets. In vitro cultures were carried out to study the cellular metabolism of protein and fat in liver and adipose tissues prepared from chicks used in feeding trials. Body weight gain was significantly improved by the administration of cimaterol to experimental diets by 2.4% (p < 0.05). Feed intake was reduced by cimaterol administration at the high energy level, but this trend was reversed at low energy level. Feed efficiency was improved by cimaterol administration and at high energy level the difference (5.7%) was significant(p < 0.05). The administration of cimaterol had no effects on percentage of abdominal fat content, giblet and neck. There was little difference in carcass yield between control and cimaterol treated group. The administration of cimaterol had no effects on nutrient metabolizability or carcass composition. The results of in vitro studies with liver tissues showed that cimaterol increased the lipolytic activities (p < 0.05) and decreased lipogenic activities (p < 0.05). In in vitro studies with acinar cell of liver tissues. cimaterol increased the amount of retained protein and decreased secreted protein at high energy level. but the trend was opposite at low energy level.

• The Korean Journal of Zoology
• /
• v.30 no.2
• /
• pp.193-209
• /
• 1987

Patterns of amylase secretion in mouse pancreatic fragments were studied over a period of time after the tissue was stimulated by acetyicholine and MNNG. MNNG is known to activate guanylate cyclase and thus increase the cGMP concentration in the pancreatic acinar cell. These amylase secretion patterns were studied to investigate the role of cGMP in reaction cascade during secretion response of the tissues stimulated by acetyicholine. Cellular response of amylase secretion in the pancreas by acetyicholine was divided into two phases. During the first phase, zymogen granules which had existed in the cells were secreted by the action of $Ca^2$+ and calmodulin immediately after secretagogue administration, this being known as the initial response. When the tissue was stimulated by acetylcholine in a $Ca^2$+-deficient medium or one containing trifluoperazine as a calmodulin antagonist, this initial response was reduced. In the second phase, newly formed zymogen granules were secreted as sustained response after protein synthesis was triggered by secretagogue. This response was provoked by an activation of protein kinase C. When either cycloheximide as a protein synthesis inhibitor or dibucaine as a protein kinase C inhibitor were added to the incubation medium, this sustained response was remarkablely depressed in the pancreatic fragments stimulated with acetylcholine. In the pancreatic acinar cell, phosphatidylinositol turnover plays an important role in the secretion response and hexachlorocyclohexane inhibits this phosphatidylinositol turnover. The pancreatic tissue treated with the hexachlorocyclohexane exhibited inhibition on both initial and sustained responses of amylase secretion by acetylcholine. MNNG also accelerated amylase secretion from the tissue gradually along incubation time. The 22 minutes fraction of the pancratic secretion after administration of both acetylcholine and MNNG showed higher amylase activity than the neighboring fractions. Guanylate cyclase potentiated the sustained response. Even if it is experimented with an indirect method, guanylate cyclase was found responsible for activation of the sustained response of a step prior to the action of protein kinase C. As conclusion, it was considered that amylase secretion in mouse pancreatic fragments stimulated by acetylcholine is a three phasic response.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.6
• /
• pp.547-550
• /
• 2001

Acinic cell carcinoma is a rare salivary gland carcinoma, usually being found in the parotid gland and is uncommon in the other major and minor salivary glands. The tumor cells consist of either serous or mucous acinar cells with few ductal or myoepithelial cell elements. The tumor is a low-grade malignancy with slow growth potential. Surgical therapy depends on tumor size and the extent of infiltration into neighboring tissues. Superficial parotidectomy or total parotidectomy is the initial method of therapy in case of acinic cell carcinoma on parotid gland. When regional neck lymph nodes are involved, the operation is combined with a neck dissection, or with radiation therapy. In the short follow up period, acinic cell carcinoma has good prognosis with 5 year survival rate after surgery is over 80%. In the long-term follow-up, however, there is a tendency to increase in recurrence or metastasis. We experienced a case of acinic cell carcinoma of parotid gland in a 57-year-old female, so we report it with literatures review.

• Journal of dental hygiene science
• /
• v.2 no.1
• /
• pp.47-51
• /
• 2002

The concentration of intracellular $Ca^{2+}$ was measured by spectrofluorometer after rat submandibular acinar cells were loaded with fura-2/AM(fura-2). After isoproterenol and octanol were administered while letting submandibular gland acinar cell placed in a perfusion chamber flow through a standard solution, the changes of $Ca^{2+}$ concentration were measured. When they were administered separately, there showed little changes of intracellular $Ca^{2+}$ concentration. When they were administered at the same time, however the concentration of intracellar $Ca^{2+}$ was shown to increase. When forskolin, an adenylate cyclase activater, was administerd together with octanol the response looked similar to the response of isoproterenol. In case of the extracellular $Ca^{2+}$ was removed by omitting $Ca^{2+}$ in standard solution and treating EGTA, isoproterenol and forskolin does not affect to the concentration of intracellular $Ca^{2+}$. Therefore, it was certified that the increase of intracellular $Ca^{2+}$ was caused from outside the cell. In order to know that the $Ca^{2+}$ influx is related with capacitative entry pathway, godolinium, blocker of that pathway was treated. With the result of that experiment there was no complete control of the increase in the concentration of intracellular $Ca^{2+}$. However, speed and amount of $Ca^{2+}$ increase was comparatively diminished.