Moretto Jillian N, Duffy Áine M, Scharfman Helen E
The Nathan Kline Institute of Psychiatric Research, Orangeburg, NY, 10962, USA.
Departments of Child and Adolescent Psychiatry, Physiology and Neuroscience, and Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.
Brain Struct Funct. 2017 Jul;222(5):2405-2419. doi: 10.1007/s00429-016-1349-z. Epub 2017 Feb 11.
Although a great deal of information is available about the circuitry of the mossy cells (MCs) of the dentate gyrus (DG) hilus, their activity in vivo is not clear. The immediate early gene c-fos can be used to gain insight into the activity of MCs in vivo, because c-fos protein expression reflects increased neuronal activity. In prior work, it was identified that control rats that were perfusion-fixed after removal from their home cage exhibited c-fos immunoreactivity (ir) in the DG in a spatially stereotyped pattern: ventral MCs and dorsal granule cells (GCs) expressed c-fos protein (Duffy et al., Hippocampus 23:649-655, 2013). In this study, we hypothesized that restraint stress would alter c-fos-ir, because MCs express glucocorticoid type 2 receptors and the DG is considered to be involved in behaviors related to stress or anxiety. We show that acute restraint using a transparent nose cone for just 10 min led to reduced c-fos-ir in ventral MCs compared to control rats. In these comparisons, c-fos-ir was evaluated 30 min after the 10 min-long period of restraint, and if evaluation was later than 30 min c-fos-ir was no longer suppressed. Granule cells (GCs) also showed suppressed c-fos-ir after acute restraint, but it was different than MCs, because the suppression persisted for over 30 min after the restraint. We conclude that c-fos protein expression is rapidly and transiently reduced in ventral hilar MCs after a brief period of restraint, and suppressed longer in dorsal GCs.
尽管关于齿状回（DG）门区苔藓细胞（MCs）的神经回路已有大量信息，但它们在体内的活动尚不清楚。即刻早期基因c-fos可用于深入了解MCs在体内的活动，因为c-fos蛋白表达反映了神经元活动的增加。在先前的研究中，已确定从饲养笼中取出后进行灌注固定的对照大鼠，其DG区呈现出空间刻板模式的c-fos免疫反应性（ir）：腹侧MCs和背侧颗粒细胞（GCs）表达c-fos蛋白（达菲等人，《海马体》23:649 - 655，2013年）。在本研究中，我们假设束缚应激会改变c-fos-ir，因为MCs表达2型糖皮质激素受体，且DG被认为与应激或焦虑相关的行为有关。我们发现，使用透明鼻锥进行仅10分钟的急性束缚，与对照大鼠相比，腹侧MCs中的c-fos-ir降低。在这些比较中，在10分钟的束缚期后30分钟评估c-fos-ir，如果评估时间晚于30分钟，c-fos-ir不再受到抑制。颗粒细胞（GCs）在急性束缚后也显示出c-fos-ir受到抑制，但与MCs不同，因为这种抑制在束缚后持续超过30分钟。我们得出结论，短暂束缚后，腹侧门区MCs中的c-fos蛋白表达迅速且短暂降低，而背侧GCs中的抑制持续时间更长。
