異丁香衍生物對抗內毒素引發低血壓及細胞激素的免疫活性

Isoeugenol derivative in lipopolysaccaride-induced rat hypotension and cytokine immunoactities

王靖菁(Ching-Chin Wang)

指導教授 ： 陳英俊 博士 ； 羅怡卿 博士

高雄醫學大學/醫學院/醫學研究所/碩士(2003年)

摘要

本研究之目的為合成以chlorophenylpiperazine為主結構之新化合物WJ-1，評估其在血清素接受體 (serotonin receptor) 及腎上腺性甲型接受體 (a-adrenoceptor) 阻斷之活性，並探討其對LPS引起之低血壓及細胞激素釋放的抑制作用。
在活體心臟血管實驗中，由靜脈注射WJ-1 (1.0 ,3.0 mg/kg) 於pentobarbital麻醉之正常血壓Wistar系大鼠，可引起心跳減慢及持續性血壓下降反應。而在較低濃度之WJ-1 (0.1 ,0.5 mg/kg ) 則沒有顯著降血壓作用。此外，於大鼠之側腦室給WJ-1 (0.3 mmol)，可引起明顯之血壓上升及心跳增加作用，並於給WJ-1 30分鐘後，再給予clonidine (38 pmol)，WJ-1可抑制clonidine引起的低血壓及心跳遲緩作用，因此WJ-1可能因具有a2接受體阻斷活性的作用，因此使血壓上升並使心跳增加。
在離體實驗結果則發現WJ-1 (10-8, 10-7, 10-6, 10-5 M) 能抑制norepinephrine, clonidine及serotonin (10-8~10-4 M) 在大鼠胸主動脈的收縮作用，並可使norepinephrine, clonidine及serotonin的濃度反應曲線呈現劑量相關地由左向右平行移動。根據以上離體實驗數據證實了此化合物具有競爭腎上腺素甲一型 (a1)、甲二型 (a2) 接受體和血清素 (5-HT2A) 接受體之活性，顯示WJ-1同時具備拮抗腎上腺素甲一型、甲二型和血清素接受體之特性，而其pA2分別是：腎上腺性甲一型接受體7.08 ±0.15，腎上腺性甲二型接受體8.54±0.12及血清素接受體9.62±0.47。
以放射線同位素來評估WJ-1之接受體結合特性：WJ-1和[3H]prazosin 在大鼠之腦皮質進行甲一型 (a1-receptor) 接受體競爭性結合實驗，其Ki值是1733；和[3H]yohimbine在大鼠之腦皮質進行甲二型 (a2-receptor) 接受體競爭性結合實驗，其Ki值是805.4；與[3H]WAY100635、 [3H] GR124753 及[3H]kentaserin在大鼠之腦皮質分別進行血清動素接受體 (5-HT receptor)： 5-HT1A、5-HT1B/1D及5-HT2A接受體競爭性結合實驗，發現其Ki值分別為1.26、63.15、49.64。此實驗數據顯示WJ-1同時具備拮抗 a1、 a2 、5-HT1A、5-HT1B/1D及5-HT2A接受體之特性。
在經由靜脈給予WJ-1 (0.5, 1 mg/kg) 30分鐘後，緊接著再注射LPS，可抑制LPS (10 mg/kg, i.v.) 引起的低血壓作用，於實驗進行中分別收集LPS注射後之三組大鼠血液（分別為第一、三、五小時），並以ELISA kit測定血漿中TNF-a、IL-1b、IL-6、IFN-g 等細胞激素濃度及血糖的變化。結果發現WJ-1可抑制LPS在第一及第三小時引起的TNF-a、IL-1b 及IFN-g 細胞激素釋放，及第三、五小時血糖的變化。
基於以上實驗結果證實WJ-1為具有甲一型 (a1-adrenoceptor)、甲二型 (a2-adrenoceptor) 受體結合、血清素一型 (5-HT1) 與血清素二型 (5-HT2) 阻斷特性之新化合物。另外，WJ-1可抑制內毒素引起的低血壓及減少具發炎作用之TNF-a、IL-1b及IFN-g 等細胞激素釋放，因此，WJ-1應有助於減低內毒素引起休克及發炎之作用。

關鍵字

異丁香 ； 內毒素

並列摘要

WJ-1 is a newly synthesized chlororphenyl-piperazine derivative. We investigated its a-adrenergic/5-HT antagonist, radioligand binding, cytokine inhibition and various pharmacological activities in rat central nervous and vascular systems in this study.
Intravenously (i.v.) injection of WJ-1 (1,3mg/kg) caused a sustained dose-dependent decrease in mean arterial blood pressure and heart rate in the normotensive Wistar rat. However, at lower concentration, WJ-1 (0.1, 0.5 mg/kg, i.v.) did not significantly decrease blood pressure. Intracerebroventricular (i.c.v.) injection of WJ-1 (0.3 mmol) caused a presser effects and inhibited clonidine (38pmol, i.c.v.)-induced hypotension and bradycardia.
In rat isolated thoracic aorta, WJ-1 (10-8, 10-7, 10-6, 10-5 M) competitively antagonized norepinephrine, clonidine and serotonin (10-8~10-4 M) induced vasocontraction in a concentration-dependent manner, which indicated it possessed a1-, a2- and 5-HT2A receptor blocking activities, respectively. The pA2 values are 7.08±0.15, 8.54±0.12 and 9.62±0.47, respectively.
The binding affinities of WJ-1 were also evaluated in [3H]prazosin (a1), [3H]yohimbine (a2), [3H]WAY100635 (5-HT1A), [3H]GR125743 (5-HT1B/1D), [3H]ketanserin (5-HT2A) binding to rats brain membranes, respectively. The Ki values respectively are 1733, 805.4, 1.26, 63.15 and 49.64. The results indicated that WJ-1 had higher binding affinity on 5-HT1A than on a1, a2, 5-HT1B and 5-HT2A receptors.
In addition, WJ-1 (0.1, 0.5mg/kg, i.v.) inhibited LPS (10mg/kg, i.v.)- induced hypotension, cytokine (TNF-a、IL-1b、IFN-g ) release and blood glucose change.
These results indicate that WJ-1 was a new α-adrenoceptor and serotonin antagonist possessing hypotensive and vasodilatory effects in central and cardiovascular systems. On the other hand, its protection against LPS-induced hypotension, cytokine release and blood glucose change might be beneficial in the treatment of inflammation and /or endotoxin shock.

並列關鍵字

isoeugenol ； lipopolysaccaride

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