Department of Histology and Neurobiology, Dokkyo Medical University, School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotsuga-gun, Tochigi 321-0293, Japan.
Department of Histology and Neurobiology, Dokkyo Medical University, School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotsuga-gun, Tochigi 321-0293, Japan.
Brain Res. 2021 Jul 1;1762:147425. doi: 10.1016/j.brainres.2021.147425. Epub 2021 Mar 15.
The amygdala plays a crucial role in anxiety-related behavior and various neuropsychiatric disorders. The offspring of dams, administered methylazoxymethanol acetate (MAM) intraperitoneally at gestational day 15, exhibit micrencephaly and anxiety-related behavior, such as hyperactivity in rearing and crossing behavior, alongside a distinct Fos expression profile in the basolateral (BLA) and central amygdala. However, the histochemical underpinnings of these changes remain to be elucidated. To determine the histochemical alterations in MAM-induced model rats, we performed Nissl staining, immunohistochemistry for parvalbumin (PV) or calbindin (Calb), and immunohistochemistry for PV in conjunction with in situ hybridization for glutamate decarboxylase (GAD). We compared immunoreactivity in the BLA between normal and MAM-induced model rats and observed a significant decrease in the number of PV-positive neurons in MAM-induced model rats; however, no significant differences in the number of Nissl- and Calb-positive neurons were observed. We did not detect any significant between-group differences with regards to the effects of environmental enrichment on the number of PV-positive neurons in the BLA. Double-labeling for GAD and PV revealed that many PV-positive neurons colocalized with digoxigenin-GAD65/67 signals. In addition, GAD/PV double-positive neurons and the total number of GAD-positive neurons in the BLA were lower in the MAM-induced model rats. These results indicate that histochemical alterations observed in the BLA of the MAM-induced model rats may attribute to an aberrant GABAergic inhibitory system.
杏仁核在与焦虑相关的行为和各种神经精神疾病中起着至关重要的作用。在妊娠第 15 天经腹腔给予甲基偶氮甲烷乙酸盐（MAM）的母鼠的后代表现出小头畸形和与焦虑相关的行为，例如在饲养和穿越行为中的过度活跃，以及外侧（BLA）和中央杏仁核中明显的 Fos 表达谱。然而，这些变化的组织化学基础仍有待阐明。为了确定 MAM 诱导模型大鼠的组织化学变化，我们进行了尼氏染色、钙结合蛋白（Calb）或钙调蛋白（PV）的免疫组织化学染色，以及与谷氨酸脱羧酶（GAD）原位杂交相结合的 PV 免疫组织化学染色。我们比较了正常和 MAM 诱导模型大鼠 BLA 中的免疫反应性，观察到 MAM 诱导模型大鼠中 PV 阳性神经元的数量明显减少；然而，Nissl 和 Calb 阳性神经元的数量没有明显差异。我们没有发现环境富集对 BLA 中 PV 阳性神经元数量的影响在两组之间有任何显著差异。GAD 和 PV 的双标记显示，许多 PV 阳性神经元与地高辛-GAD65/67 信号共定位。此外，BLA 中的 GAD/PV 双阳性神经元和 GAD 阳性神经元的总数在 MAM 诱导模型大鼠中较低。这些结果表明，MAM 诱导模型大鼠 BLA 中观察到的组织化学变化可能归因于异常的 GABA 能抑制系统。
