INVERTED-U RELATIONSHIP BETWEEN THE LEVEL OF PERIPHERAL CORTICOSTERONE AND THE MAGNITUDE OF HIPPOCAMPAL PRIMED BURST POTENTIATION
INVERTED-U RELATIONSHIP BETWEEN THE LEVEL OF PERIPHERAL CORTICOSTERONE AND THE MAGNITUDE OF HIPPOCAMPAL PRIMED BURST POTENTIATION
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DOI：
10.1002/hipo.450020409
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发表时间：
1992-10-01
期刊：
影响因子：
3.5
通讯作者：
ROSE, GM
中科院分区：
文献类型：
--
作者：
DIAMOND, DM;BENNETT, MC;ROSE, GM
研究表明，皮质酮的外周水平与两种描述良好的记忆生理模型，长时程增强（LTP）和启动爆发（PB）增强的幅度相关。在本实验中，作者研究了实验者控制的操作水平的皮质酮对海马PB增强的幅度在麻醉大鼠的影响。引发爆发增强是响应于海马连合的生理模式刺激的CA 1群体尖峰和EPSP斜率的幅度的持久（至少30分钟）增加。肾上腺切除大鼠（ADX/PELLET）皮下埋植皮质酮颗粒，控制血清皮质酮水平。在第一个实验中，血清皮质酮水平升高（应激）之间存在显着的负线性相关性（大于20 μ g/dL）和ADX/PELLET受试者中PB增强的幅度（r = 0.60，P <0.05）。在第二个实验中，皮质酮-PB增强函数的形状在低和中等水平的皮质酮下与在高水平的皮质酮下不同：在低水平（0-10 mug/dL）时呈正相关，在中等水平（11-20 mug/dL）时反应最大，在高水平（21-93 mug/dL）时呈负相关。因此，皮质酮和PB增强之间的整体关系是一个倒U函数。这些发现为皮质酮对海马可塑性表达产生浓度依赖性双相影响的假设提供了有力的支持。
Studies have shown that peripheral levels of corticosterone correlate with the magnitudes of two well-described physiological models of memory, long-term potentiation (LTP) and primed burst (PB) potentiation. In the present experiments, the authors investigated the effects of experimenter-controlled manipulations of the levels of corticosterone on the magnitude of hippocampal PB potentiation in urethane-anesthetized rats. Primed burst potentiation is a long-lasting (at least 30 minutes) increase in the amplitude of the CA1 population spike and EPSP slope in response to physiologically patterned stimulation of the hippocampal commissure. The levels of serum corticosterone were controlled by implanting corticosterone pellets in adrenalectomized rats (ADX/PELLET). In the first experiment, a significant negative linear correlation between elevated (stress) levels of serum corticosterone (greater than 20 mug/dL) and the magnitude of PB potentiation in ADX/PELLET subjects (r = 0.60, P < .05) was found. In the second experiment, the shape of the corticosterone-PB potentiation function was different at low and intermediate levels of corticosterone than it was at high levels of corticosterone: There was a positive correlation at low levels (0-10 mug/dL), a peak response at intermediate levels (11-20 mug/dL), and a negative correlation at high levels (21-93 mug/dL) of corticosterone. Thus, the overall relationship between corticosterone and PB potentiation is an inverted-U function. These findings provide strong support for the hypothesis that corticosterone exerts a concentration-dependent biphasic influence on the expression of hippocampal plasticity.