Eugenosedin-A活化大鼠肺動脈平滑肌之環化核苷酸依賴性蛋白質激酶研究

Eugenosedin-A activates cyclic nucleotide-dependent protein kinases in rat pulmonary artery smooth muscles

謝孟芬(Meng-Fen Hsieh)

指導教授 ： 吳炳男

高雄醫學大學/醫學院/醫學研究所/碩士(2010年)

摘要

先前的研究中發現 eugenosedin-A 對於抗氧化、抗發炎、自由基具有拮抗 5-HT1B/2A and ??/??1 接受器的活性。我們也發現 eugenosedin-A 在大鼠的基底動脈會經由活化cGMP/PKG 與 cAMP/PKA 兩種途徑而抑制血管的收縮。然而，目前在肺動脈內的機轉仍不清楚，所以本研究目的主要是探討 eugenosedin-A 是否也能夠調控大鼠的肺動脈內的PKG/PKA或PKC途徑。
在此研究中我們將大鼠的肺外動脈分離出來，將血管吊置在37℃的生理食鹽溶液中測量它的張力，並利用80 mM的鉀離子誘導血管的收縮，發現 eugenosedin-A (30 ?嵱)可使血管鬆弛達到一半的作用；加入水溶性鳥糞嘌呤環化酶抑制劑 (ODQ, 10 ?嵱)、腺苷環化酶抑制劑 (SQ22536, 100 ?嵱)、cGMP 依賴型蛋白激酶與 cGMP依賴型蛋白激酶抑制劑 (KT5823, 1 ?嵱 和 KT5720, 1 ?嵱) 皆會抑制eugenosedin-A的作用。另外用血清素 (100 ?嵱) 與PKC活化劑PMA (1 ?嵱) 誘導血管收縮後，發現eugenosedin-A也有抑制收縮的效果，最後再用西方墨點法觀察 PKG、PKA以及 PKC 蛋白的表現，發現eugenosedin-A會使PKG和PKA蛋白的表現增加，並抑制PKC蛋白的活化。
由實驗結果推測，eugenosedin-A 可活化 cGMP/PKG與 cAMP/PKA 兩種途徑而使肺動脈產生鬆弛的現象，且eugenosdin-A會經由抑制5-HT2A受器和5-HT1B受器以及PKC的作用，而抑制血管的收縮現象，這可能可以用來控制肺動脈的一些病變，例如肺高壓。

關鍵字

血清素 ； 蛋白激酶A ； 蛋白激酶C ； 蛋白激酶G

並列摘要

Eugenosedin-A is a 5-HT1B/2A and ??/??1-adrenergic blocker with anti-oxidative, anti-inflammatory and free radical scavenging activities. Recently, we also found that eugenosedin-A inhibits vasoconstriction by activating cGMP/protein kinase G (PKG) and cAMP/protein kinase A (PKA) pathways in basilar artery. However, it has never been investigated in pulmonary artery (PA) smooth muscles. In this study, we tried to find whether eugenosedin-A could modulate the PKG/PKA or protein kinase C (PKC) pathway in rat PAs.
Rat isolated PAs were used and incubated in physiological saline solution (PSS) at 37oC. A high K+-PSS (KPSS, 80 mM) was used to induce PA contractions and the effects can be reversed by eugenosedin-A (30 ?嵱). Eugenosedin-A-induced PA relaxations were attenuated by cGMP and cAMP inhibitors (ODQ, 10 ?嵱 and SQ22536, 100 ?嵱), and PKG and PKA inhibitors (KT5823, 1 ?嵱 and KT5720, 1 ?嵱). Eugenosedin-A also could inhibit serotonin (100 ?嵱) or PKC activator (PMA, 1 ?嵱 ) induced vasoconstriction. Western blot analysis was carried out to detect the expression of PKG, PKA, and PKC proteins. Eugenosedin-A increased the expression of PKG and PKA proteins, and inhibited PKC activation were consistent with those of functional vascular activities in PAs.
In conclusion, eugenosedin-A induced vasorelaxtion by activating both cGMP/PKG and cAMP/PKA pathway in PA. Eugenosedin-A also inhibited vasoconstriction via 5-HT2A/1B receptor and PKC. Taken together, we suggested that eugenosedin-A could be used in controlling PA-induced contractile abnormalities, e.g. pulmonary hypertension.

並列關鍵字

serotonin ； PKA ； PKC ； PKG

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