Department of Physiology, FMRP, University of São Paulo, Ribeirão Preto-SP, Brazil.
Department of Pharmacology, FMRP, University of São Paulo, Ribeirão Preto-SP, Brazil.
Sci Rep. 2017 Oct 26;7(1):14094. doi: 10.1038/s41598-017-14624-1.
Exposure to loud sounds has become increasingly common. The most common consequences of loud sound exposure are deafness and tinnitus, but emotional and cognitive problems are also associated with loud sound exposure. Loud sounds can activate the hipothalamic-pituitary-adrenal axis resulting in the secretion of corticosterone, which affects hippocampal synaptic plasticity. Previously we have shown that long-term exposure to short episodes of high intensity sound inhibited hippocampal long-term potentiation (LTP) without affecting spatial learning and memory. Here we aimed to study the impact of short term loud sound exposure on hippocampal synaptic plasticity and function. We found that a single minute of 110 dB sound inhibits hippocampal Schaffer-CA1 LTP for 24 hours. This effect did not occur with an 80-dB sound exposure, was not correlated with corticosterone secretion and was also observed in the perforant-dentate gyrus synapse. We found that despite the deficit in the LTP these animals presented normal spatial learning and memory and fear conditioning. We conclude that a single episode of high-intensity sound impairs hippocampal LTP, without impairing memory and learning. Our results show that the hippocampus is very responsive to loud sounds which can have a potential, but not yet identified, impact on its function.
暴露在响亮的声音中变得越来越普遍。响亮声音暴露的最常见后果是耳聋和耳鸣，但情绪和认知问题也与响亮声音暴露有关。响亮的声音可以激活下丘脑-垂体-肾上腺轴，导致皮质酮的分泌，从而影响海马突触可塑性。以前我们已经表明，长期暴露于短时间高强度声音会抑制海马长时程增强（LTP），而不会影响空间学习和记忆。在这里，我们旨在研究短期响亮声音暴露对海马突触可塑性和功能的影响。我们发现，一分钟 110 分贝的声音会抑制海马 Schaffer-CA1 的 LTP24 小时。80 分贝的声音暴露不会产生这种效果，也与皮质酮的分泌无关，并且在穿通-齿状回突触中也观察到了这种现象。我们发现，尽管 LTP 出现缺陷，但这些动物在空间学习和记忆以及恐惧条件反射方面表现正常。我们得出结论，单次高强度声音会损害海马 LTP，但不会损害记忆和学习。我们的结果表明，海马体对响亮的声音非常敏感，这可能对其功能产生潜在但尚未确定的影响。
