Joëls M, de Kloet E R
Department of Experimental Zoology, University of Amsterdam, The Netherlands.
J Neurosci. 1993 Sep;13(9):4082-90. doi: 10.1523/JNEUROSCI.13-09-04082.1993.
We here describe actions mediated by mineralo- and glucocorticoid receptors (MRs and GRs, respectively) on intracellularly recorded synaptic responses, evoked in rat CA1 pyramidal cells in vitro by stimulation of the Schaffer collaterals. Neurons in slices from adrenalectomized (ADX) rats, that is, where MRs and GRs are unoccupied, showed a synaptic response consisting of an EPSP, followed by a fast and a slow IPSP; the responses were apparently similar to those in slices from sham-operated rats. However, in the ADX rats, repeated electrical stimulation over a period of 80 min resulted in a gradual decline of the firing probability for synaptically driven action potentials and of the slow IPSP amplitude. Nonsynaptic responses (e.g., membrane potential, accommodation, and afterhyperpolarization) were stable during the 80 min period. Application of 3 nM aldosterone between 20 and 40 min after impalement of cells in slices from ADX rats, thus activating predominantly MRs, yielded stable synaptic and nonsynaptic responses for at least 1 hr after the onset of the steroid application. By contrast, corticosterone (30 nM), which occupies GRs in addition to MRs, reduced the amplitude of both the EPSP and slow IPSP, and the firing probability of synaptically driven action potentials, within 20 min; nonsynaptic properties remained stable. Similar results were obtained with the selective glucocorticoid RU 28362. The EPSP and fast and slow IPSPs of neurons in slices from ADX rats impaled with a time lag of 1-4 hr after the steroid application did not differ significantly from the responses of neurons impaled before steroid application.(ABSTRACT TRUNCATED AT 250 WORDS)
我们在此描述盐皮质激素受体和糖皮质激素受体（分别为MRs和GRs）对细胞内记录的突触反应所介导的作用，这些反应是在体外通过刺激大鼠CA1锥体神经元的Schaffer侧支诱发的。来自肾上腺切除（ADX）大鼠的切片中的神经元，即MRs和GRs未被占据的神经元，表现出由一个兴奋性突触后电位（EPSP）、随后是一个快速和一个慢速抑制性突触后电位（IPSP）组成的突触反应；这些反应明显类似于假手术大鼠切片中的反应。然而，在ADX大鼠中，在80分钟内重复电刺激导致突触驱动动作电位的发放概率和慢速IPSP幅度逐渐下降。非突触反应（如膜电位、适应性和超极化后电位）在80分钟内保持稳定。在ADX大鼠切片中细胞刺入后20至40分钟之间应用3 nM醛固酮，从而主要激活MRs，在类固醇应用开始后至少1小时内产生稳定的突触和非突触反应。相比之下，皮质酮（30 nM）除了占据MRs外还占据GRs，在20分钟内降低了EPSP和慢速IPSP的幅度以及突触驱动动作电位的发放概率；非突触特性保持稳定。用选择性糖皮质激素RU 28362也获得了类似的结果。在应用类固醇后1 - 4小时刺入的ADX大鼠切片中神经元的EPSP、快速和慢速IPSP与应用类固醇之前刺入的神经元的反应没有显著差异。（摘要截短于250字）
