Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine at University of South Dakota, Vermillion, SD 57069, USA.
J Exp Biol. 2011 Aug 1;214(Pt 15):2534-9. doi: 10.1242/jeb.057224.
Long-term potentiation (LTP) is a persistent increase in synaptic transmission that is thought to contribute to a variety of adaptive processes including learning and memory. Although learning is known to undergo circannual variations, it is not known whether LTP undergoes similar changes despite the importance of LTP in learning and memory. Here we report that synapses in the CNS of the medicinal leech demonstrate seasonal variation in the capacity to undergo LTP following paired presynaptic and postsynaptic stimulation. LTP was observed during the April-October period, but no LTP was observed during the November-March period. Application of forskolin, a technique often used to produce chemical LTP, failed to elicit potentiation during the November-March period. Implementing stimulation patterns that normally result in long term depression (LTD) also failed to elicit any change in synaptic strength during the November-March period. These experiments indicate that LTP and LTD can be influenced by circannual rhythms and also suggest a seasonal influence on learning and memory.
长时程增强（LTP）是一种突触传递的持久增强，被认为有助于多种适应过程，包括学习和记忆。虽然已知学习会经历年际变化，但尽管 LTP 在学习和记忆中很重要，但尚不清楚 LTP 是否会发生类似的变化。在这里，我们报告说，医用水蛭中枢神经系统中的突触在经历配对的突触前和突触后刺激后表现出 LTP 能力的季节性变化。在 4 月至 10 月期间观察到 LTP，但在 11 月至 3 月期间未观察到 LTP。应用 forskolin，一种常用于产生化学 LTP 的技术，在 11 月至 3 月期间未能引起任何增强。实施通常导致长期抑郁（LTD）的刺激模式也未能在 11 月至 3 月期间引起任何突触强度变化。这些实验表明，LTP 和 LTD 可以受到年节律的影响，并且还表明学习和记忆受到季节性的影响。
