Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, 221004 Xuzhou, China.
Center for Brain Science, State Key Laboratory of Magnetic Resonance, Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, 430071 Wuhan, China.
Proc Natl Acad Sci U S A. 2020 Feb 11;117(6):3239-3247. doi: 10.1073/pnas.1913922117. Epub 2020 Jan 28.
The olfactory system receives extensive serotonergic inputs from the dorsal raphe, a nucleus involved in control of behavior, regulation of mood, and modulation of sensory processing. Although many studies have investigated how serotonin modulates the olfactory bulb, few have focused on the anterior piriform cortex (aPC), a region important for olfactory learning and encoding of odor identity and intensity. Specifically, the mechanism and functional significance of serotonergic modulation of the aPC remain largely unknown. Here we used pharmacologic, optogenetic, and fiber photometry techniques to examine the serotonergic modulation of neural activity in the aPC in vitro and in vivo. We found that serotonin (5-HT) reduces the excitability of pyramidal neurons directly via 5-HT receptors, phospholipase C, and calcium-activated potassium (BK) channels. Furthermore, endogenous serotonin attenuates odor-evoked calcium responses in aPC pyramidal neurons. These findings identify the mechanism underlying serotonergic modulation of the aPC and shed light on its potential role.
嗅觉系统从参与行为控制、调节情绪和调节感觉处理的背侧中缝核接收广泛的血清素能输入。尽管许多研究已经调查了血清素如何调节嗅球，但很少有研究关注前梨状皮层（aPC），这是一个对嗅觉学习和气味身份和强度编码很重要的区域。具体来说，血清素能调制 aPC 的机制和功能意义在很大程度上仍然未知。在这里，我们使用药理学、光遗传学和光纤光度测定技术来研究体外和体内 aPC 中血清素能调节的神经活动。我们发现，血清素（5-HT）通过 5-HT 受体、磷脂酶 C 和钙激活钾（BK）通道直接降低锥体神经元的兴奋性。此外，内源性血清素减弱了 aPC 锥体神经元中气味诱发的钙反应。这些发现确定了 aPC 中血清素能调制的机制，并揭示了其潜在的作用。
