• The Korean Journal of Physiology and Pharmacology
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• 제6권3호
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• pp.131-138
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• 2002

Thanks to recent progress in availability of molecular and functional techniques it became possible to search for the basic molecular and cellular processes that mediate and control $HCO_3{^-}$ and fluid secretion by the pancreatic duct. The coordinated action of various transporters on the luminal and basolateral membranes of polarized epithelial cells mediates the transepithelial $HCO_3{^-}$ transport, which involves $HCO_3{^-}$ absorption in the resting state and $HCO_3{^-}$ secretion in the stimulated state. The overall process of HCO3 secretion can be divided into two steps. First, $HCO_3{^-}$ in the blood enters the ductal epithelial cells across the basolateral membrane either by simple diffusion in the forms of $CO_2$ and $H_2O$ or by the action of an $Na^+-coupled$ transporter, a $Na^+-HCO_3$ cotranporter (NBC) identified as pNBC1. Subsequently, the cells secrete $HCO_3{^-}$ to the luminal space using at least two $HCO_3{^-}$ exit mechanisms at the luminal membrane. One of the critical transporters needed for all forms of $HCO_3{^-}$ secretion across the luminal membrane is the cystic fibrosis transmembrane conductance regulator (CFTR). In the resting state the pancreatic duct, and probably other $HCO_3{^-}$ secretory epithelia, absorb $HCO_3{^-}.$ Interestingly, CFTR also control this mechanism. In this review, we discuss recent progress in understanding epithelial $HCO_3{^-}$ transport, in particular the nature of the luminal transporters and their regulation by CFTR.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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• pp.56-56
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• 2001

Increasing evidence suggests that protein-protein interaction is essential in many biological processes including epithelial transport. In this report, we present the significance of protein interactions to HCO$_3$$^{-10}$ secretion in pancreatic duct cells. In pancreatic ducts HCO$_3$$^{-10}$ secretion is mediated by CFTR-activated luminal CUHCO$_3$$^{-10}$ exchange activity and HCO$_3$$^{-10}$ absorption is achieved by Na$^{＋}$-dependent mechanism including NHE3.(omitted)

• Asian-Australasian Journal of Animal Sciences
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• 제20권1호
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• pp.60-69
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• 2007

Ruminants eating dry forage secrete large volumes of saliva which results in decreased plasma volume (hypovolemia) and the loss of $NaHCO_3$ from the blood. The present research investigated whether or not hypovolemia and the loss of $NaHCO_3$ from the blood in goats brought about by dry forage feeding actually depresses feed intake and saliva secretion, respectively. The present experiment consisted of three treatments (NI, ASI, MI). In the control treatment (NI), a solution was not infused. In the ASI treatment, i.v. infusion of artificial parotid saliva was initiated 1 h before feeding and continued for the entire 2 h feeding period. In the MI treatment, iso-osmotic mannitol solution was infused. The NI treatment showed that hematocrit and plasma total protein concentration were increased due to decreased circulating plasma volume brought about by feeding. In the ASI treatment, the fluid and $NaHCO_3$ that were lost from the blood because of a feeding-induced acceleration of saliva secretion was replenished with an intravenous infusion of artificial parotid saliva. This replenishment lessened the levels of suppression on both feeding and parotid saliva secretion. When only the lost fluid was replenished with an intravenous infusion of iso-osmotic mannitol solution in the MI treatment, the degree of feeding suppression was lessened but the level of saliva secretion suppression was not affected. These results indicate that the marked suppression of feed intake during the initial stages of dry forage feeding was caused by a feeding-induced hypovolemia while the suppression of saliva secretion was brought about by the loss of $NaHCO_3$ from the blood due to increased saliva secretion during the initial stages of feeding.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.287-299
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• 2014

Bicarbonate anion ($HCO_3{^-}$) takes the role of major buffer systems in our body by maintaining the pH at 7.4. Epithelial $HCO_3{^-}$ secretion also hydrolyzes the mucus which protects body from noxious infections. It has been widely known that such infections are closely related to $HCO_3{^-}$ permeability through membrane and, thus, increasing the $HCO_3{^-}$ permeability is essential. To evaluate the $HCO_3{^-}$ permeability through ion channels, the free energy changes relevant to ion pumping are calculated with the Integral Equation Formalism-PCM (IEF-PCM) theory. Molecular structures of various anions including $HCO_3{^-}$ were optimized with the density functional theory at the level of B3LYP/6-311++G(d,p) in gas and solution phase. In addition, the anion permeability is significantly influenced by the relative size of the anion and pore. We introduce a shifted volume factor model that describes the pore size effect when the charged solutes transfer through ion channels. We found excellent agreement between experimental and calculated permeability when our novel model of the size effect was taken into account to.

• Asian-Australasian Journal of Animal Sciences
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• 제18권10호
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• pp.1414-1420
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• 2005

The purpose of this research was to determine whether or not feeding induced hypovolemia (decreases in plasma volume) and decreases in plasma bicarbonate concentration caused by loss of $NaHCO_3$ from the blood, act to suppress feed intake and saliva secretion volumes during the initial stages of feeding in goats fed on dry forage. The animals were fed twice a day at 10:30 and at 16:00 for 2 h each time. Prior to the morning feeding, the collected saliva (3-5 kg) was infused into the rumen. During the morning 2 h feeding period (10:30 to 12:30), the animals were fed 2-3 kg of roughly crushed alfalfa hay cubes. At 16:00, the animals were fed again with 0.8 kg of alfalfa hay cubes, 200 g of commercial ground concentrate and 20 g of sodium bicarbonate. In order to compensate for water or $NaHCO_3$ lost through saliva during initial stages of feeding, a 3 h intravenous infusion (17-19 ml/min) of artificial mixed saliva (ASI) or mannitol solution (MI) was begun 1 h prior to the morning feeding and continued until the conclusion of the 2 h feeding period. The physiological state of the goats in the present experiment remained unchanged after parotid gland fistulation. Circulating plasma volume decreases caused by feeding (estimated by increases in plasma total protein concentration) were significantly suppressed by the ASI and MI treatments. During the first 1 h of the 2 h feeding period, plasma osmolality in the ASI treatment was the same as the NI (non-infusion control) treatment, while plasma osmolality in the MI treatment was significantly higher. In comparison to the NI treatment, cumulative feed intake levels for the duration of the 2 h feeding period in the ASI and MI treatments increased markedly by 56.6 and 88.3%, respectively. On the other hand, unilateral cumulative parotid saliva secretion volume following the termination of the 2 h feeding period in the ASI treatment was 50.7% higher than that in the NI treatment. MI treatment showed the same level as the NI treatment. The results of the present experiment proved that the humoral factors involved in the suppression of feeding and saliva secretion during the initial stages of feeding in goats fed on dry forage, are feeding induced hypovolemia and decrease in plasma $HCO_3^-$ concentration caused by loss of $NaHCO_3$ from the blood.

• The Korean Journal of Physiology and Pharmacology
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• 제22권1호
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• pp.91-99
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• 2018

Protein phosphatase 1 (PP1) is involved in various signal transduction mechanisms as an extensive regulator. The PP1 catalytic subunit (PP1c) recognizes and binds to PP1-binding consensus residues (FxxR/KxR/K) in NBCe1-B. Consequently, we focused on identifying the function of the PP1-binding consensus residue, $^{922}FMDRLK^{927}$, in NBCe1-B. Using site-directed mutagenesis and co-immunoprecipitation assays, we revealed that in cases where the residues were substituted (F922A, R925A, and K927A) or deleted (deletion of amino acids 922-927), NBCe1-B mutants inhibited PP1 binding to NBCe1-B. Additionally, by recording the intracellular pH, we found that PP1-binding consensus residues in NBCe1-B were not only critical for NBCe1-B activity, but also relevant to its surface expression level. Therefore, we reported that NBCe1-B, as a substrate of PP1, contains these residues in the C-terminal region and that the direct interaction between NBCe1-B and PP1 is functionally critical in controlling the regulation of the ${HCO_3}^-$ transport. These results suggested that like IRBIT, PP1 was another novel regulator of ${HCO_3}^-$ secretion in several types of epithelia.

• Asian-Australasian Journal of Animal Sciences
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• 제21권4호
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• pp.538-546
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• 2008

Large-type goats eating dry forage secreted large volumes of saliva which resulted in the loss of $NaHCO_3$ from the blood and decreased plasma volume (hypovolemia). This research investigated whether or not the loss of $NaHCO_3$ from the blood and hypovolemia brought about by dry forage feeding actually depresses feed intake in large-type goats under free drinking conditions. The present experiment consisted of three treatments (NI, ASI, MI). All treatments in this experiment were carried out under free drinking conditions. In the NI control (NI), a solution was not infused. In the ASI treatment, i.v. infusion of artificial saliva was initiated 2 h before feeding and was continued for a total of 3 h concluding 1 h after the commencement of the feeding perod. In the MI treatment, mannitol solution was infused to replenish only water lost from the blood in the form of saliva. The hematocrit and plasma total protein concentrations during feeding in the NI control were observed to be higher than pre-feeding levels. This indicated that dry forage feeding-induced hypovolemia was caused by the accelerated secretion of saliva during the initial stages of feeding in freely drinking large-type goats. Increases in hematocrit and plasma total protein concentrations due to dry forage feeding were significantly suppressed by the ASI treatment. While hematocrit during feeding in the MI treatment was significantly lower than the NI control, plasma total protein concentrations were not different. From these results, it is clear that the MI treatment was less effective than the ASI treatment in mitigating the decreases in plasma volume brought about by dry forage feeding. This indicates that plasma volume increased during dry forage feeding in the ASI treatment which inhibited production of angiotensin II in the blood. The ASI treatment lessened the levels of suppression on dry forage feeding, but the MI treatment had no effect on it under free drinking conditions. The results indicate that despite the free drinking conditions, increases in saliva secretion during the initial stages of dry forage feeding in large-type goats caused $NaHCO_3$ to be lost from the blood into the rumen which in turn caused a decrease in circulating plasma volume and resulted in activation of the renin-angiotensin system and thus feeding was suppressed.

• Applied Microscopy
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• 제19권2호
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• pp.119-137
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• 1989

Turtle bladder의 상피조직(上皮組織)과 세포막(細胞膜) 투과성(透過性)을 분석하기 위하여 동결절단법(凍結切斷法)을 적용(適用)하여 전자현미경(電子顯微鏡) 관찰을 하였으며 그 결과 다음과 같이 요약(要約)된다. 1. 방광상피(膀胱上皮)의 3가지 주요세포형(主要細胞形)은 granular-cell, ${\alpha}$ 및 ${\beta}$형(形)의 CA-rich cell로서 구분된다. 2. 과립성세포(顆粒性細胞)의 주요기능(主要機能)은 $Na^+$ 재흡수(再吸收)이며, 두 단계(段階)의 수송과정(輸送過程)으로 설명되며 정단세포막(頂端細胞膜)을 통한 $Na^+$의 세포내(細胞內) 확산이동(擴散移動)과 그후 기저막(基底膜)에 위치한 $Na^{+}\;-K^{+}$ 펌프에 의한 능동수송과정(能動輸送過程)이다. 3. ${\alpha}$ 및 ${\beta}$형(形) CA-rich cell은 $Na^+$ 수송(輸送)에 관여하지 않으며, ${\alpha}$형(形)의 CA-cell은 정단세포막(頂端細胞膜)의 proton펌프를 이용하여 proton 분필(分泌)에 관여한다. 또한 ${\beta}$형(形)의 CA-cell는 정단세포막(頂端細胞膜)을 통한 $HCO_{3}^-$ 분필수송(分泌輸送)의 기능을 가지고 있다. 4. 동결절단법(凍結切斷法)의 적용하에 세포막표면(細胞膜表面)의 특성(特性)을 관찰한 바, ${\alpha}$형(形)의 CA-cell의 정단세포막(頂端細胞膜)은 proton펌프를 함유하는 것으로 보이는 intramembrane particle이 다수 관찰되고 있으며, ${\beta}$형(形) CA-cell은 기저세포막(基底細胞膜)에서 이와같은 intramembrane particle이 나타나고 있다. 5. 상술(上述)한 두 type의 CA-cell에서 수송특성(輸送特性)의 차이는 proton 및 $HCO_{3}^-$ 분필수송(分泌輸送)이 서로 반대의 방향으로 일어나는 것으로 사료된다.

• 약학회지
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• 제39권4호
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• pp.401-410
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• 1995

Pharmacolinetic profiles of omeprazole enteric coated granules including Ramezole$^\circledR$, Losec$^\circledR$, omeprazole-Na and omeprazole-resin salt were studied using the crossover design in rats and rabbits. The absorption variance of the preparations at the altered pH condition of the gastrointestinal tract was also studied. After oral administration of four omeprazole enteric coated pellets (10mg/kg) with and without concomitant administration NaHCO$_{3}$ (5 mg/ml, 60 mM) in the rats, the differences of absorplion rate and extent were evaluated. In the NaHCO$_{3}$, administration group, the T$_{max}$ appeared to be 2~10 times shorter than water administration group, and the $C_{max}$ also increased to about 4 times, and the AUC increased to about 2.5 times. Pharmacokinetic parameters of four omeprazole enteric coated pellets in rats showed no statistical significance (ANOVA, P>0.05) in both groups. In the crossover study, the second dosed drug showed 4~5 times increased bioavailability than first dosed drug, which shows the strong carry-over effect of acid secretion of the first dosed drug. The differences of the pharmacokinetic parameters of the two test formulations (Losec$^\circledR$ and omeprazole-resin) showed no statistical significance.

• Asian-Australasian Journal of Animal Sciences
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• 제16권8호
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• pp.1118-1125
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• 2003

Research was carried out to clarify whether a suppression of dry forage intake during the early stages of feeding in ruminants is caused by feeding induced hypovolemia which is produced by the accelerated secretion of parotid saliva. Goats with a parotid fistula were fed roughly crushed alfalfa hay cubes, commercial ground concentrate feed and $NaHCO_3$ twice daily (10:00-12:00, 16:00-18:00). The animals were free access to drinking water all day prior to, during and after experiments. The animals were intraruminally infused every day prior to the morning feeding period with parotid saliva collected from the parotid fistula over a 24 h period. The present experiment consisted of two treatments, non-infusion (RNI) and intraruminal infusion of parotid saliva (RSF). In the RSF treatment, 4-5 kg of parotid saliva (280-290 mOsm/l) collected over a 24 h period was intraruminally infused 1 h prior to the commencement of the morning feeding. During feeding, eating and parotid saliva secretion rates were measured. Blood samples were also periodically collected from the jugular vein. During and after 2 h feeding, water intakes were measured, respectively. These measurements were used to define thirst levels. It is thought that rumen fill in the RSF treatment was higher than the RNI treatment. Plasma osmolality in the RSF treatment increased in the first half of the 2 h feeding period due to the intraruminal infusion of parotid saliva. Therefore, parotid saliva secretion rates in the RSF treatment were lower than the RNI treatment for 30 min period from 30 to 60 min after the commencement of feeding. On the other hand, plasma total protein concentration and hematocrit in the RSF treatment decreased by 3.2 and 3.3% prior to the commencement of feeding due to the intraruminal infusion of parotid saliva. In the first half of the 2 h feeding period, plasma total protein concentration and hematocrit in the RSF treatment showed a tendency to decrease compared to the RNI treatment. Thirst level in the RSF treatment during feeding was approximately 31.3% less than the RNI treatment. Upon the completion of the 2 h feeding period, cumulative feed intake in the RSF treatment was significantly larger (19.7%) than the RNI treatment. The results suggest that a suppression of dry forage intake during the early stages of feeding in goats is partly caused by feeding induced hypovolemia, which is produced by the accelerated secretion of parotid saliva.