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Na+/H+ exchanger와 HCO-3 transporter에 의한 흰쥐 타액선 선세포내 pH 조절

Other Titles
 박동범  ;  서정택  ;  손흥규  ;  이종갑 
 Journal of the Korean Academy of Pediatric Dentistry (대한소아치과학회지), Vol.25(2) : 352-367, 1998 
Journal Title
 Journal of the Korean Academy of Pediatric Dentistry (대한소아치과학회지) 
Issue Date
Intracellular pH (pHi) plays an important role in the regulation of cellular processesby influencing the acitivity of various enzymes in cells. Therefore, almost every type ofmammalian cell possesses an ability to regulate its pHi. One of the most prominentmechanisms in the regulation of pHi is Na+/H+ exchanger.This exchanger has been known to be activated when cells are stimulated by thebinding of agonist to the muscarinic receptors. Therefore, the aims of this study were tocompare the rates of H+ extrusion throughNa+/H+ exchanger before and during muscarinic stimulationand to investigate the possible existence of HCO-3transporter which is responsible for the continuous supply ofHCO-3 ion to saliva.Acinar cells were isolated from the rat mandibular salivary glands and loaded withpH- sensitive fluoroprobe, 2′, 7′ -bis(2-carboxyethyl)-5(6)-carboxyfluorescein(BCECF),for 30min at room temperature.Cells were attached onto the coverglass in the perfusion chamber and the chages inpHi were measured on the iverted using spectrofluorometer.1. By switching the perfusafe from HCO-3 free toHCO-3 buffered solution, pHi decreased by 0.39±0.02 pHunits follows by a slow increase at an initial rate of 0.04±0.007 pH units/min. The rateof pHi increase was reduced to 0.01±0.002 pH units/min by the simultaneous addition of1 mM amiloride and 100μM DIDS.2. An addition and removal of NH+4 caused a decrease inpHi which was followed by an increase in pHi. The increase of pHi was almostcompletely blocked by 1mM amiloride in HCO-3-freeperfusate which implied that the pHi increase was entired dependent on the activation ofNa+/H+ exchanger in HCO-3-freecondition.3. An addition of 10μM carbachol increased the initial rate of pHi recovery from 0.16±0.01pH units/min to 0.28±0.03pH units/min.4. The initial rate of pHi decrease induced by 1mM amiloride was also increased bythe exposure of the acinar cells to 10μM carbachol (0.06±0.008pH unit/min) comparedwith that obtained before carbachol stimulation (0.03±0.004pH unit/min)5. The intracellular buffering capacity β1 was 14.31±1.82 at pHi 7.2-7.4 and β1increased as pHi decreased.6. The rate of H+ extrusion through Na+/H+exchanger was greatly enhanced by the stimulation of the cells with 10μM carbacholand there was an alkaline shift in the activity of the exchanger.7. An intrusion mechanism of HCO-3 was identified in ratmandibular salivary acinar cells. Taken all together, 1 observed 3-fold increase inNa+/H+ exchanger by the stimulation of the acinar cells with10μM carbachol at pH 7.25. In addition, I have found an additional mechanism for theregulation of pHi which transported HCO-3 into the cells.
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2. College of Dentistry (치과대학) > Dept. of Oral Biology (구강생물학교실) > 1. Journal Papers
Yonsei Authors
Seo, Jeong Taeg(서정택) ORCID logo https://orcid.org/0000-0003-2697-0251
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