Serotonin, via HTR2 receptors, excites neurons in a cortical-like premotor nucleus necessary for song learning and production.
Serotonin, via HTR2 receptors, excites neurons in a cortical-like premotor nucleus necessary for song learning and production.
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DOI：
10.1523/jneurosci.2281-11.2011
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发表时间：
2011-09-28
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影响因子：
--
通讯作者：
Perkel DJ
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文献类型：
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作者：
Wood WE;Lovell PV;Mello CV;Perkel DJ
5-羟色胺（5-HT）是一种神经调节剂，对神经发育、学习和记忆、情绪和感知都很重要。血清素系统的功能障碍是抑郁症和其他临床上重要的情绪障碍的核心，并与学习障碍有关。在哺乳动物中，脑干中缝核释放的5-HT可以调节皮质神经元的功能特性，影响感觉和运动加工。鸟类的背颌也有血清素能神经元，这表明5-羟色胺在感觉和运动处理中起着类似的作用，可能调节了鸟鸣背后的大脑回路。为了研究这种可能性，我们在雄性斑胸草雀的大脑切片中测量了5-羟色胺对运动前翼突核投射神经元自发放电的影响。这些神经元被认为类似于皮层V层锥体神经元。5-HT显著和可逆地增强RA神经元的内源性放电。使用体外药理激动剂和拮抗剂，我们确定这种作用是通过HTR2受体介导的，我们通过原位杂交验证了HTR2受体的表达。最后，局部给药5-羟色胺选择性再摄取抑制剂（SSRI）氟伏沙明显示内源性5-羟色胺足以在体内介导这种作用。这些发现揭示了血清素对歌唱系统回路的生理调节作用，并提出了血清素在调节歌曲产生和/或学习中的新作用；进一步了解5-羟色胺在该系统中的作用可能有助于阐明这种神经调节剂在人类社会互动和运动可塑性中的复杂作用。
Serotonin (5-HT) is a neuromodulator that is important for neural development, learning and memory, mood, and perception. Dysfunction of the serotonin system is central to depression and other clinically important mood disorders and has been linked with learning deficits. In mammals, 5-HT release from the raphe nuclei in the brainstem can modulate the functional properties of cortical neurons, influencing sensory and motor processing. Birds also have serotonergic neurons in the dorsal raphe, suggesting that 5-HT plays similar roles in sensory and motor processing, perhaps modulating brain circuitry underlying birdsong. To investigate this possibility we measured the effects of 5-HT on spontaneous firing of projection neurons in the premotor robust nucleus of the arcopallium in brain slices from male zebra finches. These neurons are thought be akin to cortical layer V pyramidal neurons. 5-HT dramatically and reversibly enhanced the endogenous firing of RA neurons. Using pharmacological agonists and antagonists in vitro, we determined this action is mediated via HTR2 receptors, which we verified are expressed by in situ hybridization. Finally, focal administration of the serotonin selective reuptake inhibitor (SSRI) fluvoxamine revealed that endogenous 5-HT is sufficient to mediate this effect in vivo. These findings reveal a modulatory action of serotonin on the physiology of the song system circuitry and suggest a novel role of serotonin in regulating song production and/or learning; further understanding of the role of 5-HT in this system may help illuminate the complex role of this neuromodulator in social interactions and motor plasticity in humans.