The mechanisms of the modulation of excitatory synaptic transmission by endogenously synthesized neurosteroids.

神经类固醇在中枢神经系统中独立于外周内分泌腺重新合成，并且被认为通过调节海马中的突触功能来促进学习和记忆。然而，由于大多数关于神经甾体效应的研究报告都是专门用外源性神经甾体进行的，因此很少有人知道内源性合成的神经甾体在多大程度上有助于海马突触功能。 我们的最新研究表明，内源性合成的神经甾体组成性增强兴奋性突触传递的少年男性海马脑片的齿状回。 在这项研究中，我们揭示了内源性神经甾体的调节作用的机制。 此外，我们发现内源性神经甾体对老年大鼠兴奋性突触传递的增强作用减少。

Neurosteroids are synthesized de novo in the central nervous system independently of the peripheral endocrine glands and believed to promote learning and memory by modulating synaptic function in the hippocampus. However, as most of the reported studies on the neurosteroid effects were performed exclusively with exogenously applied neurosteroids, little is known to what degree endogenously synthesized neurosteroids contribute to the hippocampal synaptic function. Our latest study showed that endogenously synthesized neurosteroids constitutively potentiate excitatory synaptic transmission in the dentate gyrus of juvenile male hippocampal slices. In this study, we revealed the mechanisms underlying the modulatory actions of endogenous neurosteroids. In addition, we found a decrease in the potentiation of excitatory synaptic transmission by endogenous neurosteroids in aged rats.