Cyclic AMP and cyclic GMP activate protein kinase G in cavernosal smooth muscle cells: old age is a negative factor
Cyclic AMP and cyclic GMP activate protein kinase G in cavernosal smooth muscle cells: old age is a negative factor
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DOI：
10.1046/j.1464-410x.2002.02643.x
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发表时间：
2002-04-01
影响因子：
4.5
通讯作者：
Lue, TF
中科院分区：
文献类型：
--
作者：
Lin, CS;Liu, X;Lue, TF
目的 探讨蛋白激酶G-I（PKG-I）在幼年和老年大鼠海绵体平滑肌细胞（CSMC）中的表达和激活情况。材料与方法采用免疫组化、逆转录聚合酶链反应、Western blot等方法检测大鼠阴茎中PKG-I的表达。将从幼年（1只6周龄）和年老（28月龄）大鼠中分离的CSMC培养为单层细胞培养物，并在不同时期用不同剂量的cAMP或cGMP处理。然后分析其蛋白中血管舒张刺激磷蛋白（VASP）、磷酸化VASP（丝氨酸239）、PKG-I和蛋白激酶A（PKA）的表达。结果在大鼠阴茎血管和CSMC中检测到PKG-I表达。年轻和年老大鼠的PKG-I表达水平几乎没有差异。在整个测试期间（LIP至24小时），用不同剂量的cAMP或cGMP处理CSMC并没有改变VASP的表达水平。相反，S239处的VASP磷酸化水平，即PKG-I激活水平，取决于cAMP和cGMP的剂量以及治疗持续时间。 cAMP 或 cGMP 长时间治疗（24 小时）导致 PKG-I 和 PKA 下调。虽然 cAMP 和 cGMP 在几乎所有方面都产生了非常相似的结果，但在一项测试中存在差异，其中 cGMP 在 28 月龄大鼠的 CSMC 中产生的活化 PKG-I 比 cAMP 少得多。 结论 我们首次提供了 CSMC 中 PKG-I 激活的证据。 cAMP 和 cGMP 均能够激活 CSMC 中的 PKG-I。年龄似乎会损害 PKG-I 响应 cGMP 的能力。
Objective To investigate protein kinase G-I (PKG-I) expression and activation in cavernosal smooth Muscle cells (CSMC) of young and old rats.Materials and methods PKG-I expression in rat penis was examined by immunohistochemical staining, reverse transcription-polymerase chain reaction, and Western blot analysis. CSMC isolated from young (1 6-week-old) and old (28-month-old) rats were grown as monolayer cell cultures and treated with different dosages of cAMP or cGMP for different periods. Their proteins were then analysed for the expression of vasodilator-stimulated phosphoprotein (VASP), phosphorylated VASP (at serine 239), PKG-I, and protein kinase A (PKA).Results PKG-I expression was detected in the vascular and CSMC of the rat penis. There was little or no difference in the level of PKG-I expression between young and old rats. Treatment of CSMC with different dosages of cAMP or cGMP did not change the expression levels of VASP throughout the entire test period (LIP to 24 h). In contrast, the level of VASP phosphorylation at S239, i.e. the level of PKG-I activation, depended on the dosages of cAMP and cGMP and on the duration of treatment. Prolonged treatment (24 h) with either cAMP or cGMP resulted in down-regulation of both PKG-I and PKA. While cAMP and cGMP produced very similar results in nearly every aspect, there was a difference in one test, in which cGMP produced much less activated PKG-I than cAMP in the CSMC of 28-month-old-rats.Conclusions For the first time we provide evidence for PKG-I activation in CSMC. Both cAMP and cGMP were capable of activating PKG-I in CSMC. Age seemed to compromise the ability of PKG-I in response to cGMP.