Excitatory amino acid induced currents of isolated murine hypothalamic neurons and their suppression by 2,3-butanedione monoxime.
Excitatory amino acid induced currents of isolated murine hypothalamic neurons and their suppression by 2,3-butanedione monoxime.
复制标题
兴奋性氨基酸诱导分离的小鼠下丘脑神经元的电流及其被 2,3-丁二酮单肟的抑制。
DOI：
10.1016/0028-3908(95)00100-k
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发表时间：
1995
影响因子：
4.7
通讯作者：
McArdle,JJ
中科院分区：
文献类型：
--
作者：
Ye,JH;McArdle,JJ
用全细胞记录技术研究了兴奋性氨基酸对新鲜分离的小鼠下丘脑神经元离子电流的影响。L-谷氨酸或N-甲基-D-天冬氨酸与甘氨酸结合可产生一种快速上升的电流，该电流随激动剂的持续存在而衰减。相比之下，海藻酸海流并没有衰退。在激动剂持续存在的情况下，Quisquate诱发电流保持一个稳定的幅度，而在负−50 mV的保持电位下出现一个快速衰减期。联合应用2，3-丁二酮单肟(BDM)可逆地抑制每种激动剂产生的电流。BDM抑制红藻氨酸诱导电流的详细研究揭示了两个成分。起效快的成分不涉及磷酸酶作用，因为500μMATP-γ-S或蛋白激酶抑制剂(H-7,200μM)不改变BDM后的电流抑制或恢复。因此，BDM的S效应的这一部分的可能机制是直接阻断红藻氨酸激活的离子通道。然而，用30 mM的BDM预先孵育神经元，降低了它们单独对红藻氨酸的后续反应。在常规的全细胞记录中，用含有三磷酸腺苷-γ-S的溶液透析的神经元没有看到这种持久的BDM效应。此外，暴露于H-7阻止了BDM预先孵育抑制的红藻氨酸反应的恢复。这些发现表明，BDM通过“化学磷酸酶”作用导致下丘脑神经元对KA反应的持续抑制。
Ionic currents induced by excitatory amino acids were investigated for freshly isolated murine hypothalamic neurons with whole cell recording techniques. L-glutamate or N-methyl-D-aspartate (NMDA), in combination with glycine, resulted in a rapidly rising current which decayed in the continued presence of agonist. In contrast, kainate currents did not decay. While quisqualate-induced current maintained a steady amplitude in the continued presence of agonist, a rapid decay phase appeared at holding potentials negative to − 50 mV. Co-application of 2,3-butanedione monoxime (BDM) reversibly inhibited the currents due to each agonist. Detailed study of BDM suppression of kainate-induced current revealed two components. A component with a rapid onset did not involve phosphatase action since 500 μMATP-γ-S or a protein kinase inhibitor (H-7, 200 μM) did not alter current suppression or recovery after BDM. Thus, the probable mechanism for this component of BDM 's effect is direct block of the kainate-activated ion channel. However, preincubating neurons with 30 mM BDM reduced their subsequent response to kainate alone. This persistent effect of BDM was not seen for neurons dialyzed with a solution containing ATP-γ-S during conventional whole cell recording. Furthermore, exposure to H-7 prevented recovery of the kainate response suppressed by preincubation in BDM. These findings suggest that BDM causes sustained suppression of the kainate response of hypothalamic neurons via a “chemical phosphatase” action.