钙调神经磷酸酶在大鼠肺组织合成和释放鸟苷素中的作用

Role of calcineurin in the synthesis and release of guanylin in lung tissue of rats

研究钙调神经磷酸酶 (CaN)依赖的信号通路在肺组织合成和释放鸟苷素中的作用。以乙酰胆碱 (Ach)刺激孵育的大鼠离体肺组织 ,用放射免疫法测定肺组织和孵育液中鸟苷素的含量 ,以及肺组织CaN活性 ;同时观察CaN抑制剂环孢霉素A(CsA)对鸟苷素生成的影响。结果发现 :( 1)Ach呈浓度依赖性增加孵育液中鸟苷素的含量 ,孵育4h后 ,分别较对照组增加了 63 2 % ,13 5 1%和 15 6 6% (P <0 0 1)。肺组织鸟苷素的含量 ,分别较对照组增加了2 9% ,3 4 3 % (P <0 0 1)和 42 0 % (P <0 0 1)。 ( 2 )Ach 10 -5mol L呈时间依赖性增加孵育液中鸟苷素的含量 ,在 2 ,4,6h分别较对照组增加了 90 7% ,13 5 1%和 173 8% (P <0 0 1) ;肺组织鸟苷素含量分别增加了 7 0 % ,3 4 3 % (P <0 0 1)和 3 3 8% (P <0 0 1)。 ( 3 )CaN抑制剂CsA呈浓度 ( 10 -8、10 -7和 10 -6mol L)依赖性抑制Ach 10 -5mol L刺激的孵育液中鸟苷素的含量 ,分别下降了 9% (P <0 0 5 ) ,2 0 4% (P <0 0 5 )和 3 6 1% (P <0 0 1)。肺组织鸟苷素的含量分别降低 2 3 % ,10 1% (P <0 0 5 )和 2 0 3 % (P <0 0 1)。 ( 4 )Ach 10 -5mol L作用 4h可刺激肺组织CaN活性增加2 1 5 % (P <0 0 5 ) ,CsA 10 -6mol L则抑制Ach刺激的肺组织CaN活性 (P

To investigate the role of calcineurin (CaN)-dependent signal transduction pathway in the synthesis and release of guanylin in lung tissue slices. The isolated lung tissue slices of rats were incubated with acetylcholine (Ach). The amount of guanylin in the lung tissue and incubation medium was measured by RIA kit. CaN activity in the lung tissue was measured by spectrophotometer. The effect of cyclosporin A (CsA), inhibitor of CaN on the synthesis and release of guanylin was also studied. The results were as follows: (1) Ach stimulated the release of guanylin in a dose-dependent manner, increasing by 63.2%,135.1% and 156.6%(P<0.01), respectively as compared with control. The amount of guanylin in lung tissue was increased by 2.9%,34.3%(P<0.01)and 42.0%(P<0.01), respectively. (2) Ach 10 -5mol/L stimulated the release of guanylin in a time-dependent manner, with the increase rate by 90.7%,135.1% and 173.8%(P<0.01)for 2,4,6h, respectively. The amount of guanylin in lung tissue was increased by 7.0%,34.3%(P<0.01)and 33.8%(P<0.01)for 2,4,6h, respectively. (3) CsA inhibited the release of guanylin stimulated by Ach 10 -5mol/L in a dose-dependent(10 -8～10 -6mol/L)manner by 9%(P<0.05),20.4%(P<0.05)and 36.1%(P<0.01), respectively. The amount of guanylin in lung tissue was decreased by 2.3%,10.1%(P<0.05)and 20.3%(P<0.01), respectively. (4) Ach10 -5mol/L increased CaN activity by 21.5%(P<0.05), while CsA 10 -6mol/L inhibited CaN activity induced by Ach(P<0.01). Acetylcholine stimulated the synthesis and release of guanylin in lung tissue slices, in which CaN may play as an important transduction signal.