長期給予懷孕母鼠嗎啡對其所生幼鼠腦中NMDA受體表現及CaM kinase II活性的影響

Effect of prenatal treatment of morphine on the expression of the NMDA receptor and the activity of the CaM kinase II in the developing rat brain

郭峰旭(Fong Hsu Kuo)

指導教授 ： 葉健全

臺北醫學大學/醫學院/醫學科學研究所/碩士(2001年)

摘要

嗎啡成癮的懷孕婦女，其嬰兒於出生後雖然在外表上並無畸形的現象，但長期來看則發現到這類幼兒其學習能力異常及情緒控制能力有不穩定的情形，這樣的情況有報告指出可能是因為嬰兒於出生前即暴露於嗎啡的環境之下而使的嬰兒於腦部神經突觸、神經傳導物質的釋放以及接受器的表現上發生不正常的改變所導致。先前本實驗室曾經利用一種長期動物給藥模式，即是於母鼠懷孕前一週給予皮下注射每公斤2毫克的嗎啡，在確定其懷孕之後即每週增加每公斤1毫克的劑量，直到幼鼠出生後30天。而在幼鼠出生後的第7天、14天、30天、60天分別給予斷頭取腦，並利用受體結合實驗來定量個腦中大腦皮質及海馬迴的NMDA receptor 密度。結果發現控制組所生幼鼠其大腦皮質及海馬迴中於出生後第14天NMDA 受體的表現量有短暫性高峰的現象，但在嗎啡組的幼鼠身上並沒有發現到這樣的情況。這樣的現象可能是嗎啡導致NMDA 受體的各個亞型的表現下降所致。而本實驗室過去利用相同的動物模式來進一步的探討是否給予在嗎啡的狀況下將使得發育中的老鼠腦中大腦皮質、海馬迴、紋狀體這些腦區其NMDA 受體的各個亞型的表現量產生改變，結果發現嗎啡組所生幼鼠在大腦皮質區、海馬迴及紋狀體其NMDA受體亞型蛋白於出生後第7天及第14天比控制組所生幼鼠下降許多。因此我們推論這種現象可能與幼鼠體內嗎啡的濃度有關，若是讓幼鼠出生後即終止嗎啡給予，使其血中嗎啡濃度消失而產生脫癮，這樣的現象對於NMDA受體的減量調控是否仍然存在。故本實驗研究的第一個方向在於瞭解於幼鼠出生後立即停止給予母鼠嗎啡，來觀察幼鼠腦中各天數NMDA receptor各亞型的表現。 NMDA receptor的活化即為活化CaM kinase II必須的過程，在生理上，活化後的CaM kinase II具有調節神經傳導物質的釋放與合成、碳水化合物的代謝、細胞骨架的組合、分解和神經可塑性及增強突觸間的傳導並誘導產生LTP(Long —term protentiation)。而以往本實驗室發現嗎啡會導致幼鼠於發育期間腦中大腦皮質區、海馬迴及紋狀體中NMDA 受體的密度下降，而這樣的現象是否會使的CaM kinase II的活化受到影響。所以本實驗第二個研究重點在於利用西方墨點法觀察長期施打嗎啡下的懷孕母鼠其所生幼鼠及嗎啡於幼鼠出生後不繼續打下去的組別，其腦中活化型式的CaM kinase II表現量是否與正常的幼鼠有所差異 ; 同時偵測幼鼠於大腦皮質及海馬迴內CaM kinase II的活性來加以比較西方墨點法所得到的結果。結果指出長期給予懷孕母鼠嗎啡其所生的幼鼠其腦中大腦皮質、海馬迴及紋狀體內NMDA 受體各亞型及具活化狀態的CaM kinase II 的表現將受到改變 ;而嗎啡於幼鼠出生後不繼續打下去的組別所觀察到的活化狀態CaM kinase II的結果與嗎啡於幼鼠出生後繼續打下去的組別的結果相同。

關鍵字

興奮性麩氨酸受體

並列摘要

Children born to morphine addicted mother have been shown to suffer acute withdrawal syndrome after birth and develop a long—term neuropsychological sequels. Considerable evidences have confirmed that prenatal exposure to morphine also produce significant alteration in developing brain including retardation in neurite growth, change in neurotransmitter release and the expression of receptor .Our previous studies found that ontogenic expression of the NMDA receptor in this rats is different to that of control rat by lacking an overshooting of NMDA receptor density on PND14. It is possible that this transient change is due to decrease in the subtype of the NMDA receptor or a decrease in the numbers of the synapse that containing the NMDA receptor. We used the same morphine treatment animal modal to explore whether morphine treatment could induce a change in the NMDA receptor subunits in the developing rat brain. Now, we further explore if morphine treatment until rat born could also induce a change in the NMDA receptor subunits in the developing rat brain. Furthermore whether morphine treatment will change the expression of activity of the CaM kinase II in the developing rat brains.This results suggested that the chronic treatment of morphine on dams rats will change the expression of NMDA receptor subunit and the expression of activity of the CaM kinase II .

並列關鍵字

NMDA receptor

參考文獻

Basheer R, Yang J, Tempel A (1992) Chronic prenatal morphine treatment decreases G alpha s mRNA levels in neonatal frontal cortex. Brain Research. Developmental Brain Research 70:145-148.

Bashir ZI, Tam B, Collingridge GL (1990) Activation of the glycine site in the NMDA receptor is necessary for the induction of LTP. Neuroscience Letters 108:261-266.

Bem JL, Peck R (1992) Dextromethorphan. An overview of safety issues. Drug Safety 7:190-199.

Bokesch PM, Marchand JE, Connelly CS, Wurm WH, Kream RM (1994) Dextromethorphan inhibits ischemia-induced c-fos expression and delayed neuronal death in hippocampal neurons. Anesthesiology 81:470-477.

Casado-Flores J, Bano-Rodrigo A, Romero E (1990) Social and medical problems in children of heroin-addicted parents. A study of 75 patients. American Journal of Diseases of Children 144:977-979.