MICROELECTRODE DETERMINATION OF OXYNTIC CELL PH IN INTACT FROG GASTRIC-MUCOSA - EFFECT OF HISTAMINE
MICROELECTRODE DETERMINATION OF OXYNTIC CELL PH IN INTACT FROG GASTRIC-MUCOSA - EFFECT OF HISTAMINE
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DOI：
10.1007/bf00376210
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发表时间：
1992-12-01
影响因子：
4.5
通讯作者：
FROMTER, E
中科院分区：
文献类型：
--
作者：
DEBELLIS, L;CURCI, S;FROMTER, E
用双管pH微电极测定了完整林蛙胃底黏膜细胞内pH(pH(I))。在显微手术切除浆膜肌层后，将浆膜侧面朝上的组织固定在两个半腔之间，并将单个细胞刺穿。连续记录静息状态(0.1mmo1/L)和刺激时(0.5 mmo1/L组胺)的跨上皮电位差(V(T))、阻力(R(T))以及浆膜电位(V(S))和pH(I)。用pH(O)=7.36的HCO3-/CO2缓冲林格液灌流时，V(T)和R(T)分别为-21.7、SD+/-6.0 mV和229+/-83 omega cm2(n=17)，而V(S)和pH(I)平均为-57.3+/-6.9 mV和7.4+/-0.11(n=25)。后一个值比最近用显微荧光技术在分离的细胞、腺体或完整组织上获得的所有pH(I)测量的碱性要大得多。这种差异的部分原因可能是在以前的大多数研究中使用了无HCO3的溶液，因为我们观察到这种溶液将pH(I)降低到6.89+/-0.18(n=4)。同样，与最近的文献相反，组胺在HCO3-/CO2缓冲溶液中的应用导致进一步的瞬时碱化，pH单位为0.12+/-0.05(n=8)。由于在胃腺腔意外穿刺处，我们注意到H+的分泌在组胺应用后大约5分钟才开始，因此我们推断组胺诱导的初始碱化并不反映对H+/K+ATPase泵的刺激。另一种可能是组胺引起的其他离子转运体的激活或失活，一种可能是基侧Na+/H+和Cl-/HCO3-交换器的激活。
Intracellular pH (pH(i)) of acid-secreting cells was measured in intact gastric fundus mucosa of Rana esculenta with double-barrelled pH microelectrodes. Tissues were mounted, serosal side up, between two half chambers and individual cells were impaled after microsurgical removal of the serosal muscle layer. Transepithelial potential difference (V(t)) and resistance (R(t)) as well as serosal cell membrane potential (V(s)) and pH(i) were continuously recorded at rest (0.1 mmol/l cimetidine) or during stimulation (0.5 mmol/l histamine). During chamber perfusion with HCO3-/CO2-buffered Ringer solution of pH(o) = 7.36, V(t) and R(t) were -21.7, SD +/- 6.0 mV and 229 +/- 83 OMEGA cm2 (n = 17) while V(s) and pH(i) averaged -57.3 +/- 6.9 mV and 7.4 +/- 0.11 (n = 25). The latter value is considerably more alkaline than all recent pH(i) measurements obtained with microspectrofluorometric techniques on isolated cells, glands or intact tissue. The difference may in part be explained by use of HCO3--free solutions in most of the previous studies because we observed that such solutions decrease pH(i) to 6.89 +/- 0.18 (n = 4). Again, in contrast to recent literature, application of histamine in HCO3-/CO2-buffered solution led to further transient alkalinization by 0.12 +/- 0.05 pH unit (n = 8). Since in accidental punctures of the gastric gland lumen we noticed that H+ secretion only began approximately 5 min after histamine application, we conclude that the histamine-induced initial alkalinization does not reflect stimulation of the H+/K+ ATPase pump. Alternatively, it may result from histamine-induced activation or inactivation of other ion transporters, one possibility being activation of basolateral Na+/H+ and Cl-/HCO3- exchangers.