LACRIMAL GLAND INOSITOL TRISPHOSPHATE ISOMER AND INOSITOL TETRAKISPHOSPHATE PRODUCTION
LACRIMAL GLAND INOSITOL TRISPHOSPHATE ISOMER AND INOSITOL TETRAKISPHOSPHATE PRODUCTION
复制标题
DOI：
10.1152/ajpgi.1990.259.2.g274
复制
发表时间：
1990-08-01
影响因子：
--
通讯作者：
MURPHY, SA
中科院分区：
文献类型：
--
作者：
DARTT, DA;DICKER, DM;MURPHY, SA
在泪腺中，胆碱能激动剂通过从磷脂酰肌醇二磷酸产生肌醇三磷酸（IP 3）来刺激蛋白质和电解质/水分泌。为了确定产生哪种IP 3异构体以及在分泌激活过程中是否产生肌醇四磷酸（IP 4），大鼠眶外腺腺泡被[3 H]肌醇标记并由胆碱能激动剂卡巴胆碱刺激。水溶性肌醇磷酸盐分离阴离子交换色谱使用Dowex柱或高效液相色谱。使用Ca 2+染料fura-2通过荧光测量细胞内Ca 2+浓度（[Ca 2 +]i）。卡巴胆碱（10-3 M）在0-60 s的刺激过程中产生了时间依赖性的1，4，5-IP 3，1，3，4-IP 3和1，3，4，5-IP 4水平的增加。1，4，5-IP 3水平迅速增加，随后1，3，4-IP 3和1，3，4，5-IP 4水平缓慢上升。一个3秒卡巴胆碱（10-8至10-2 M）的刺激引起浓度依赖性上升的1，4，5-IP 3水平。卡巴胆碱（10-9至10-2 M）以浓度依赖性方式增加[Ca 2 +]i。卡巴胆碱（10-3 M）使[Ca 2 +]i在10 s时达到最大值，到60 s时[Ca 2 +]i下降38%。1，4，5-IP 3水平的最大增加发生在卡巴胆碱浓度高于[Ca 2 +]i或蛋白质分泌的增加。我们的结论是，胆碱能刺激泪腺迅速增加1，4，5-IP 3水平，这是负责初始增加[Ca 2 +]i和初始快速阶段的蛋白质和液体分泌。胆碱能刺激也增加了1，3，4-IP 3和1，3，4，5-IP 4，但更慢;无论是沿着或与1，4，5-IP 3一起作用，它们都可以解释分泌的较慢阶段。
In the lacrimal gland, cholinergic agonists stimulate protein and electrolyte/water secretion by producing inositol trisphosphate (IP3) from phosphatidylinositol bisphosphate. To determine which IP3 isomers were produced and whether inositol tetrakisphosphate (IP4) was produced during activation of secretion, rat exorbital gland acini were [3H]inositol-labeled and stimulated by the cholinergic agonist carbachol. Water-soluble inositol phosphates were separated by anion-exchange chromatography using Dowex columns or high-performance liquid chromatography. Intracellular Ca2+ concentration ([Ca2+]i) was measured by fluorescence using the Ca2+ dye fura-2. Carbachol (10-3 M) produced a time-dependent increase in 1,4,5-IP3, 1,3,4-IP3, and 1,3,4,5-IP4 levels during 0-60 s of stimulation. The 1,4,5-IP3 level increased rapidly and was followed by a slower rise in 1,3,4-IP3 and 1,3,4,5-IP4 levels. A 3-s carbachol (10-8 to 10-2 M) stimulation caused a concentration-dependent rise in the 1,4,5-IP3 level. Carbachol (10-9 to 10-2 M) increased [Ca2+]i in a concentration-dependent manner. Carbachol (10-3 M) increased [Ca2+]i to a maximum level by 10 s; by 60 s [Ca2+]i decreased by 38%. The maximum increase in 1,4,5-IP3 levels occurred at a higher carbachol concentration than the increase in [Ca2+]i or protein secretion. We concluded that cholinergic stimulation of the lacrimal gland rapidly increased 1,4,5-IP3 levels, which was responsible for the initial increase in [Ca2+]i and initial rapid phase of protein and fluid secretion. Cholinergic stimulation also increased 1,3,4-IP3 and 1,3,4,5-IP4, but more slowly; either acting along or with 1,4,5-IP3, they could account for the slower phase of secretion.