A role for brain glucocorticoid receptors in contextual fear conditioning: dependence upon training intensity
A role for brain glucocorticoid receptors in contextual fear conditioning: dependence upon training intensity
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DOI：
10.1016/s0006-8993(97)01420-0
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发表时间：
1998-03-09
期刊：
影响因子：
2.9
通讯作者：
Sandi, C
中科院分区：
文献类型：
--
作者：
Cordero, MI;Sandi, C
我们研究了皮质类固醇激素在建立和长期表达的背景恐惧条件反射的可能参与，并质疑皮质类固醇的作用是否可能依赖于刺激强度在训练。实验包括：（i）在条件化时，向在1 mA或0.4 mA电击强度下训练的大鼠脑室内施用两种类型的细胞内皮质类固醇受体的特异性拮抗剂;和（ii）在将大鼠条件化至0.2 mA电击后施用皮质酮。结果表明，管理的II型糖皮质激素，但不是I型盐皮质激素，受体拮抗剂调节大鼠的中间休克条件衰减长期表达的上下文恐惧条件。然而，在高电击强度条件反射之前用拮抗剂处理未能影响恐惧条件反射的程度。此外，腹膜内注射皮质酮，训练后立即给予大鼠在低冲击强度，增强长期表达的恐惧反应。结果支持的观点，即训练后水平的循环皮质酮，通过与中央II型糖皮质激素受体的相互作用，调制的强度，记忆上下文恐惧条件反射的建立和维持。(C)1998年Elsevier Science B.V.
We studied the possible involvement of corticosteroids in the establishment and long-term expression of contextual fear conditioning and questioned whether a corticosteroid action might be dependent upon stimulus intensity at training. Experiments included: (i) the intracerebroventricular administration of specific antagonists for the two types of intracellular corticosteroid receptors to rats trained at either 1 mA or 0.4 mA shock intensity at conditioning; and (ii) the administration of corticosterone after conditioning rats to 0.2 mA shocks. The results showed that the administration of a type II glucocorticoid, but not a type I mineralocorticoid, receptor antagonist before conditioning rats to the intermediate shock condition attenuated long-term expression of contextual fear conditioning. However, treatment with the antagonists before conditioning to the high shock intensity failed to influence the extent of fear conditioning. In addition, an intraperitoneal corticosterone injection, given immediately after training rats at the low shock intensity, enhanced long-term expression of the fear response. The results support the view that post-training levels of circulating corticosterone, through an interaction with central type II glucocorticoid receptors, modulate the strength to which memory for contextual fear conditioning is established and maintained. (C) 1998 Elsevier Science B.V.