Takeda Atsushi, Imano Sachie, Itoh Hiromasa, Oku Naoto
Department of Medical Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka, Japan.
Brain Res. 2006 Nov 6;1118(1):52-7. doi: 10.1016/j.brainres.2006.08.025. Epub 2006 Sep 7.
Zinc release in the lateral nucleus of the amygdala was examined using rat brain slices. The lateral and basolateral nuclei in the amygdala were evidently stained by Timm's sulfide-silver staining method. When the amygdala including both the nuclei was stimulated with 100 mM KCl by means of in vivo microdialysis, extracellular zinc concentration was increased significantly. Zinc release in the lateral nucleus of the amygdala innervated by the entorhinal cortex was next examined in brain slices double-stained with zinc and calcium indicators. Extracellular zinc signal (ZnAF-2) in the lateral nucleus was increased with intracellular calcium signal (calcium orange) during delivery of tetanic stimuli to the entorhinal cortex. Both the increases were completely inhibited by addition of 1 micro M tetrodotoxin, a sodium channel blocker. Furthermore, calcium signal in the lateral nucleus during delivery of tetanic stimuli to the entorhinal cortex was increased in the presence of 10 micro M CNQX, an AMPA/KA receptor antagonist, and this increase was facilitated by addition of 1 mM CaEDTA, a membrane-impermeable zinc chelator. The present study suggested that zinc is released in the lateral nucleus of the amygdala by depolarization of the entorhinal neurons. In the lateral nucleus, zinc released may suppress the increase in presynaptic calcium signal.
使用大鼠脑片研究杏仁核外侧核中的锌释放。通过Timm硫化银染色法可明显观察到杏仁核中的外侧核和基底外侧核被染色。当通过体内微透析用100 mM KCl刺激包含这两个核的杏仁核时，细胞外锌浓度显著增加。接下来，在用锌和钙指示剂双重染色的脑片中研究了内嗅皮质支配的杏仁核外侧核中的锌释放。在向内嗅皮质传递强直刺激期间，外侧核中的细胞外锌信号（ZnAF-2）随着细胞内钙信号（钙橙）增加。添加1 μM河豚毒素（一种钠通道阻滞剂）可完全抑制这两种增加。此外，在存在10 μM CNQX（一种AMPA/KA受体拮抗剂）的情况下，向内嗅皮质传递强直刺激期间外侧核中的钙信号增加，并且添加1 mM CaEDTA（一种膜不可渗透的锌螯合剂）可促进这种增加。本研究表明，内嗅神经元去极化可导致杏仁核外侧核释放锌。在外侧核中释放的锌可能会抑制突触前钙信号的增加。
