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 [SCZ]globus pallidus 苍白球 |
幸福的小孩 发表于 2006/9/20 10:59:22 |
| 蒼白球是基底神經節間接環路的重要核，在機體運動功能調節中發揮重要作用。近年來，蒼白球在基底神經節正常及異常功能調節中的重要性已日漸受到重視。然而，目前對蒼白球內各種神經遞質系統的功能活動瞭解較少。GABA是蒼白球主要的神經遞質。採用電生理記錄、免疫組織化學及行為測試等實驗方法，人們對大鼠蒼白球GABA能神經傳遞系統的受體分佈及功能活動有了新的認識。形態學研究揭示，蒼白球存在GABA(下標 A)、受體及其苯二氮卓結合位點和GABA(下標 B)受體。在亞細胞水準，GABA(下標 A)受體主要位於對稱性突觸（GABA能突觸）的突觸後膜，而GABA(下標 B)受體則位於劉稱性突觸和非對稱性突觸（興奮性突觸）的突觸前膜及突觸後膜。功能學研究進一步揭示，激活蒼白球突觸前膜GABA(下標 B)自身和異源性受體可分別減少GABA和谷氨酸釋放；啟動突觸後膜GABA(下標 B)受體，可引起蒼白球神經元超極化。除GABA(下標 B)受體外，激活蒼白球GABA(下標 A)受體苯二氮卓結合位點及阻斷GABA重攝取可延長GABA電流持續時間，從而改變蒼白球神經元興奮性。與離體實驗結果相一致，激活蒼白球GABA(下標 B)受體和苯二氮卓結合位點及阻斷GABA重攝取可引起整體動物旋轉行為。蒼白球GABA神經遞質系統與帕金森病病因學及癲癇發病有關。已證實，蒼白球神經元放電頻率的降低及簇狀放電的產生與帕金森病運動減少及靜山險震顫等症狀直接相關。此外，電生理及行為學實驗發現，新型抗癲癇藥物替加平可調節蒼白球神經元功能活動，這為進一步瞭解蒼白球與癲癰發病的關係提供了新的理論及實驗依據。
The globus pallidus occupies a critical position in the ‘indirect’ pathway of the basal ganglia and, as such, plays an important role in the modulation of movement. In recent years, the importance of the globus pallidus in the normal and malfunctioned basal ganglia is emerging. However, the function and operation of various transmitter systems in this nucleus are largely unknown. GABA is the major neurotransmitter involved in the globus pallidus. By means of electrophysiological recording, immunohistochemistry and behavioral studies, new information on the distribution and functions of the GABAergic neurotransmission in the rat globus pallidus has been generated. Morphological studies revealed the existence of GABA(subscript A) receptor, including its benzodiazepine binding site, and GABAB receptor in globus pallidus. At subcellular level, GABA(subscript A) receptors are located at the postsynaptic sites of symmetric synapses (putative GABAergic synapses). However, GABAB receptors are located at both pre- and postsynaptic sites of symmetric, as well as asymmetric synapses (putative excitatory synapses). Consistent with the morphological results, functional studies showed that activation of GABA(subscript B) receptors in globus pallidus reduces the release of GABA and glutamate by activating presynaptic auto- and heteroreceptors, and hyperpolarizes pallidal neurons by activating postsynaptic receptors. In addition to GABA(subscript B) receptor, activation of GABA(subscript A) receptor benzodiazepine binding site and blockade of GABA uptake change the activity of globus pallidus by prolonging the duration of GABA current. In agreement with the in vitro effect, activation of GABA(subscript B) receptor, GABA(subscript A) receptor benzodiazepine binding site and blockade of GABA uptake cause rotation in behaving animal. Furthermore, the GABA system in the globus pallidus is involved in the etiology of Parkinson’s disease and regulation of seizures threshold. It has been demonstrated that the abnormal hypoactivity and synchronized rhythmic discharge of globus pallidus neurons associate with akinesia and resting tremor in parkinsonism. Recent electrophysiological and behavioral studies indicated that the new anti-epileptic drug, tiagabine, is functional in globus pallidus, which may present more information to understand the involvement of globus pallidus in epilepsy | |
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Cathy's Sweet Base
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blog名称:cathy的糖果屋
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建立时间:2006年9月17日 | |
