Regulation of bicarbonate secretion as fluid excretion in the salivary ducts

在本研究中，我们研究了排除荧光染料从管腔卡巴胆碱（CCh）在孤立的腮腺小叶间导管段，以澄清的能力，导管的液体分泌与碳酸氢盐分泌。在灌注荧光染料的过程中，CCh降低了管腔中的荧光强度，并且CCh从离体管腔中冲洗出被荧光染料染色的小的粘性物质。醋甲唑胺和去除外部Ca^2+抑制了Cch诱导的胆管荧光清除。一个主要部分被抑制的清除碳酸氢盐的灌流液和DPC，但不是低浓度的外部CT，布美他尼或DIDS。斑块研究表明存在Ca^2+激活的阴离子通道，而gramieidin穿孔斑块分析表明碳酸氢根是分离的导管细胞外向电流的主要部分。这些结果提示卡巴胆碱可能通过Ca^2+激活的DPC敏感阴离子通道和HCO_3^-分泌促进大鼠腮腺小叶内导管的液体分泌。

In the present study, we investigated the exclusion of fluorescent dye from the duct lumen by carbachol (CCh) in isolated parotid interlobular duct segments to clarify the ability of the ducts for the fluid secretion with bicarbonate secretion. CCh decreased the fluorescent intensity in the duct lumen during the superfusion of the fluorescent dye, and CCh flushed out small viscous substances stained with the fluorescent dye from isolated duct lumen. Methazolamide and removal of external Ca^<2+> suppressed CCh-induced clearance of the duct fluorescence. A major portion was inhibited by removal of bicarbonate in the superfusion solution and DPC, but not low concentration of external CT, bumetanide or DIDS. Patch-clump investigation indicated the presence of Ca^<2+> -activated anion channels, and gramieidin-perforated patched analysis indicated that bicarbonate was a major portion of outward currents in the isolated duct cells. These results suggest that carbachol evoles fluid secretion possibly through Ca^<2+> -activated, DPC-sensitive anion channels with HCO_3^- secretion in the rat parotid intralobular ducts.