Benedetti A, Baroni G S, Marucci L, Mancini R, Bassotti C, Macarri G
Department of Gastroenterology, University of Ancona, School of Medicine, Italy.
Alcohol Clin Exp Res. 1995 Feb;19(1):216-25. doi: 10.1111/j.1530-0277.1995.tb01495.x.
The aim of this study was to gain information on intracellular pH (pHi) regulation in periportal (PP) and perivenular (PV) hepatocytes isolated from rats pair-fed liquid diets with either ethanol (T rats) or isocaloric carbohydrates (C rats). pHi was analyzed by the pH-sensitive dye BCECF in perfused subconfluent hepatocyte monolayers. Cells were acid-loaded by pulse exposure to NH4Cl and were alkali-loaded by suddenly reducing external CO2 and HCO3- (from 10% and 50 mM, respectively, to 5% and 25 mM) at constant pHout. In cells from C rats: (a) steady-state pHi was higher in PP than in PV hepatocytes in the presence, but not in the absence, of bicarbonate; (b) pHi recovery from an acid load was 35% higher in PP than in PV cells in the presence of HCO3-, whereas it was similar in HCO3(-)-free experiments; and, on the contrary, (c) pHi recovery from an alkaline load was 30% higher in PV than in PP cells. In cells from T rats: (a) steady-state pHi was always lower than in cells isolated from pair-fed animals; (b) steady-state pHi was similar in PP and PV hepatocytes either in the presence or absence of bicarbonate in the perfusate; (c) pHi recovery from an acid load was not significantly different in PP and PV cells either in the presence of HCO3- or in HCO3(-)-free experiments; and (d) pHi recovery from an alkaline load was similar in PP and PV cells. Our data suggest that chronic ethanol treatment selectively modifies pHi by affecting the activity of ion transport mechanisms regulating pHi in PP and PV hepatocytes isolated from rat liver.
本研究的目的是获取关于从成对喂养液体日粮的大鼠中分离出的肝门周（PP）和肝静脉周（PV）肝细胞内pH（pHi）调节的信息，这些大鼠分别喂食乙醇（T组大鼠）或等热量碳水化合物（C组大鼠）。通过对灌流的亚汇合肝细胞单层中对pH敏感的染料BCECF进行分析来测定pHi。细胞通过脉冲暴露于NH4Cl进行酸加载，并通过在恒定细胞外pH下突然降低外部CO2和HCO3-（分别从10%和50 mM降至5%和25 mM）进行碱加载。在C组大鼠的细胞中：（a）在存在碳酸氢盐的情况下，PP肝细胞中的稳态pHi高于PV肝细胞，但在不存在碳酸氢盐的情况下则不然；（b）在存在HCO3-的情况下，PP细胞从酸负荷中恢复的pHi比PV细胞高35%，而在无HCO3-的实验中两者相似；相反，（c）PV细胞从碱负荷中恢复的pHi比PP细胞高30%。在T组大鼠的细胞中：（a）稳态pHi总是低于从成对喂养动物中分离出的细胞；（b）在灌流液中存在或不存在碳酸氢盐的情况下，PP和PV肝细胞中的稳态pHi相似；（c）在存在HCO3-或无HCO3-的实验中，PP和PV细胞从酸负荷中恢复的pHi没有显著差异；（d）PP和PV细胞从碱负荷中恢复的pHi相似。我们的数据表明，慢性乙醇处理通过影响调节从大鼠肝脏分离出的PP和PV肝细胞中pHi的离子转运机制的活性，选择性地改变了pHi。
