Trout L, Gatzy J T, Ballard S T
Department of Physiology, College of Medicine, University of South Alabama, Mobile, Alabama 36688, USA.
Am J Physiol. 1998 Dec;275(6):L1095-9. doi: 10.1152/ajplung.1998.275.6.L1095.
Inhibitors of Cl- and HCO-3 secretion reduce acetylcholine-induced liquid, but not mucin, secretion by bronchial submucosal glands [S. K. Inglis, M. R. Corboz, A. E. Taylor, and S. T. Ballard. Am. J. Physiol. 272 (Lung Cell. Mol. Physiol. 16): L372-L377, 1997]. The present study quantified contributions of Cl- and HCO-3 transport to volume and composition of acetylcholine-induced liquid secretion by airway epithelium. When distal bronchi were excised from 33 pigs and treated with 10 microM acetylcholine, the airways secreted 13.4 +/- 0.7 microliter. cm-2. h-1. Bumetanide (10 microM) pretreatment reduced acetylcholine-induced liquid and Cl- secretion rates by approximately 70%, but HCO-3 secretion fell by only 40%. Dimethylamiloride (DMA; 100 microM) pretreatment reduced Cl- secretion rates by approximately 15%, but HCO-3 secretion fell 47%. DMA alone had little effect on liquid secretion. When airways were pretreated with both bumetanide and DMA, acetylcholine-induced liquid secretion was nearly abolished. We conclude that about three-fourths of acetylcholine-induced liquid secretion in distal bronchi is dependent on Cl- secretion. Most of the remaining response is driven by HCO-3 secretion. We speculate that the principal source of this liquid is submucosal glands. Crossover inhibition of bumetanide on HCO-3 secretion and DMA on Cl- secretion implies modulation of anion secretion secondary to changes in cell electrolyte composition.
氯离子和碳酸氢根分泌抑制剂可减少乙酰胆碱诱导的支气管黏膜下腺液体分泌，但不影响黏蛋白分泌[S.K.英格利斯、M.R.科尔博兹、A.E.泰勒和S.T.巴拉德。《美国生理学杂志》272卷（肺细胞与分子生理学16）：L372 - L377，1997年]。本研究定量分析了氯离子和碳酸氢根转运对气道上皮乙酰胆碱诱导的液体分泌量及成分的贡献。从33头猪身上切除远端支气管并用10微摩尔/升乙酰胆碱处理后，气道分泌量为13.4±0.7微升·厘米⁻²·小时⁻¹。布美他尼（10微摩尔/升）预处理使乙酰胆碱诱导的液体和氯离子分泌速率降低约70%，但碳酸氢根分泌仅下降40%。二甲基氨氯吡脒（DMA；100微摩尔/升）预处理使氯离子分泌速率降低约15%，但碳酸氢根分泌下降47%。单独使用DMA对液体分泌影响很小。当气道同时用布美他尼和DMA预处理时，乙酰胆碱诱导的液体分泌几乎完全被抑制。我们得出结论，远端支气管中约四分之三的乙酰胆碱诱导的液体分泌依赖于氯离子分泌。其余大部分反应由碳酸氢根分泌驱动。我们推测这种液体的主要来源是黏膜下腺。布美他尼对碳酸氢根分泌的交叉抑制以及DMA对氯离子分泌的交叉抑制意味着细胞电解质组成变化继发的阴离子分泌调节。
