Institute of Zoology, Jagiellonian University, Ingardena 6, 30-060 Krakow, Poland.
Brain Res. 2010 Mar 12;1320:28-33. doi: 10.1016/j.brainres.2010.01.031. Epub 2010 Jan 18.
We studied the potential for induction of long-term potentiation (LTP) in slices of the dentate gyrus of C57BL/6 mouse, prepared 24h after 1, 3, 7, 14 or 21 successive daily neck restraint sessions lasting for 10min. In slices from control animals and mice restrained only once, LTP (155+/-2% of baseline) was evident for at least 2h, but LTP was impaired after 3 sessions of neck restraint. This effect could be blocked by administration of the glucocorticoid receptor (GR) antagonist RU38486 before each restraint. One day after 3 restraint sessions the levels of plasma corticosterone, GR and mineralocorticoid receptor (MR) proteins remained elevated. After 7 neck restraint sessions the LTP level returned to normal; after 14 and 21 restraint sessions LTP was enhanced. LTP enhancement after 14 daily restraint sessions was not blocked by the GR antagonist RU38486 administered before each restraint; the MR antagonist RU28318 blocked LTP induction completely. After 14 daily restraint sessions the level of GR and MR proteins did not differ from the control and the plasma corticosterone level remained slightly elevated. These data indicate that repeated stress imposed by brief neck restraint bidirectionally modulates the potential for LTP in the dentate gyrus in a manner dependent on the number of daily restraint sessions.
我们研究了在 C57BL/6 小鼠经过 1、3、7、14 或 21 次连续每日颈部束缚 10 分钟后 24 小时制备的齿状回切片中长时程增强（LTP）的诱导潜力。在来自对照动物和仅束缚一次的小鼠的切片中，LTP（155 +/- 2%的基线）至少持续 2 小时，但在经过 3 次颈部束缚后，LTP 受损。这种效应可以通过在每次束缚前给予糖皮质激素受体（GR）拮抗剂 RU38486 来阻断。在 3 次束缚后一天，血浆皮质酮、GR 和盐皮质激素受体（MR）蛋白的水平仍然升高。经过 7 次颈部束缚后，LTP 水平恢复正常；经过 14 和 21 次颈部束缚后，LTP 增强。在经过 14 次每日束缚后，GR 拮抗剂 RU38486 在每次束缚前给药并不能阻断 LTP 增强；MR 拮抗剂 RU28318 完全阻断了 LTP 的诱导。在经过 14 次每日束缚后，GR 和 MR 蛋白的水平与对照无差异，血浆皮质酮水平仍略有升高。这些数据表明，短暂颈部束缚引起的重复应激以依赖于每日束缚次数的方式双向调节齿状回中 LTP 的潜力。
