Young J A, Cook D I, Evans L A, Pirani D
J Dent Res. 1987 Feb;66(2):531-6. doi: 10.1177/00220345870660022401.
The effects of substituting gluconate for extracellular Cl, and of treatment with various ion transport blockers, on cytosol pH (pHi) and secretion by the acetylcholine stimulated rat mandibular gland were studied in vitro. Gluconate replacement increased pHi from 7.12 +/- 0.02 to 7.27 +/- 0.04, caused secretory rate to fall by 75%, and increased salivary HCO3 from 14 +/- 0.9 mmol/L to 67 +/- 1.5 mmol/L. Furosemide (1 mmol/L), which blocks Na-K-2Cl symports and Cl-HCO3 antiports, had effects similar to those of gluconate replacement, except that secretion was reduced only by 59%. Bumetanide (1 mmol/L), which blocks only Na-K-2Cl symports, caused a 67% reduction in secretion rate, but it had little effect on pHi and caused only a small rise in salivary HCO3 concentration. SITS (1 mmol/L), which blocks Cl-HCO3 antiports, increased pHi to 7.26 +/- 0.03 and induced a small rise in the secretory rate. Methazolamide and acetazolamide (1 mmol/L), both of which inhibit carbonic anhydrase and may also block anion channels, increased pHi to 7.43 +/- 0.02 and 7.20 +/- 0.03, respectively, but had no effect on secretory rate, and reduced salivary HCO3 slightly. Ba (3 mmol/L), tetraethylammonium (10 mmol/L), and decamethonium (5 mmol/L) all caused marked but reversible reductions in secretory rate, consistent with the known actions of these agents on K channels. Ba, however, also appeared to act as a Ca antagonist, an action that it seemed to share with Mn ions (5 mmol/L).(ABSTRACT TRUNCATED AT 250 WORDS)
体外研究了用葡萄糖酸盐替代细胞外氯离子以及用各种离子转运阻滞剂处理对乙酰胆碱刺激的大鼠下颌下腺细胞溶质pH（pHi）和分泌的影响。用葡萄糖酸盐替代使pHi从7.12±0.02升高至7.27±0.04，使分泌率下降75%，并使唾液HCO3从14±0.9 mmol/L增加至67±1.5 mmol/L。呋塞米（1 mmol/L）可阻断Na-K-2Cl同向转运体和Cl-HCO3反向转运体，其作用与用葡萄糖酸盐替代相似，只是分泌仅减少59%。布美他尼（1 mmol/L）仅阻断Na-K-2Cl同向转运体，使分泌率降低67%，但对pHi影响不大，仅使唾液HCO3浓度略有升高。SITS（1 mmol/L）可阻断Cl-HCO3反向转运体，使pHi升高至7.26±0.03，并使分泌率略有升高。甲醋唑胺和乙酰唑胺（1 mmol/L）均抑制碳酸酐酶，也可能阻断阴离子通道，分别使pHi升高至7.43±0.02和7.20±0.03，但对分泌率无影响，并使唾液HCO3略有降低。钡（3 mmol/L）、四乙铵（10 mmol/L）和十烃季铵（5 mmol/L）均导致分泌率显著但可逆的降低，这与这些药物对钾通道的已知作用一致。然而，钡似乎还作为钙拮抗剂起作用，这种作用似乎与锰离子（5 mmol/L）相同。（摘要截断于250字）
