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Identification of neurotransmitter receptors on Muller cells and their function.

Muller 细胞上神经递质受体的鉴定及其功能。

基本信息

批准号：
07671933
负责人：
WAKAKURA Masato
金额：
$ 1.47万
依托单位：
Kitasato Universtiy
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

We obtained previously considerable evidence indicating the expression of AMPA/kainater receptors not only by neurons but also Muller cells. Cytosolic calcium transients following an agonist administration to Muller cells cultured from adult rabbit retinas were examined with spectrofluorometry using fura-2 AM.Calcium transients occurred more in number for neurotoxic kainate exposed that control cells, suggesting the AMPA/kainate receptors develop be novo in pathological state. Using the above methods to detect calcium transients, we found approximately 50% of neurons cultured from neonatal rat retinas responded to muscarine at 50 muM , but 50 muM was requisite for the formation of calcium transients in 50% of cultured Muller cells. The muscarine inducement of calcium transients was blocked by atropine. The agonist of M1, McN-A-343 eliciteed the most significant calcium transients both in neurons and Muller cells. Thus, Muller cells appeared to possess the less sensitive muscarinic receptor including at least M1. P_1-/P_2-purinergic receptor agonists including A2 and P2y induced calcium transients in cultured Muller cells. Muller cells are thus shown guite likely to possess the P_1-/P_2-purinergic receptors. A new excitotoxic amino acid, dysiherbaine is also studied and it induced calcium transients in Muller cells but appeared not to be mediated by known AMPA/Kainate receptors, since the receptor antagonists (CNQX and DNQX) to be mediated by kmown AMPM/Kainate receptors, since the receptor antagonists (CNQX and DNQX) could not block the transients.

我们获得了以前相当多的证据表明，AMPA/kainater受体的表达不仅由神经元，但也穆勒细胞。用Fura-2 AM荧光分光光度法检测了成年兔视网膜培养的Muller细胞在激动剂作用下胞浆内钙瞬变的变化。神经毒性红藻氨酸作用下胞浆内钙瞬变的数量比对照细胞多，提示病理状态下AMPA/红藻氨酸受体的新生。使用上述方法检测钙瞬变，我们发现大约50%的新生大鼠视网膜培养的神经元对50 μ M的毒蕈碱有反应，但50 μ M是50%培养的Muller细胞中钙瞬变形成所必需的。毒蕈碱诱导的钙瞬变可被阿托品阻断。M1的激动剂McN-A-343在神经元和Muller细胞中都引起最显著的钙瞬变。因此，Muller细胞似乎具有较不敏感的毒蕈碱受体，至少包括M1。P_1-/P_2-嘌呤受体激动剂A_2和P_2 γ诱导培养的Muller细胞内钙瞬变。提示Muller细胞可能具有P_1/P_2嘌呤能受体。还研究了一种新的兴奋性毒性氨基酸dysiherbaine，其在Muller细胞中诱导钙瞬变，但似乎不是由已知的AMPA/红藻氨酸受体介导的，因为受体拮抗剂（CNQX和DNQX）由已知的AMPA/红藻氨酸受体介导，因为受体拮抗剂（CNQX和DNQX）不能阻断瞬变。