Hattox Alexis, Li Ying, Keller Asaf
Department of Anatomy & Neurobiology and The Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Neuron. 2003 Jul 17;39(2):343-52. doi: 10.1016/s0896-6273(03)00391-x.
Many rodents explore their environment by rhythmically palpating objects with their mystacial whiskers. These rhythmic whisker movements ("whisking"; 5-9 Hz) are thought to be regulated by an unknown brainstem central pattern generator (CPG). We tested the hypothesis that serotonin (5-HT) inputs to whisking facial motoneurons (wFMNs) are part of this CPG. In response to exogenous serotonin, wFMNs recorded in vitro fire rhythmically at whisking frequencies, and selective 5-HT2 or 5-HT3 receptor antagonists suppress this rhythmic firing. In vivo, stimulation of brainstem serotonergic raphe nuclei evokes whisker movements. Unilateral infusion of selective 5-HT2 or 5-HT3 receptor antagonists suppresses ipsilateral whisking and substantially alters the frequencies and symmetry of whisker movements. These findings suggest that serotonin is both necessary and sufficient to generate rhythmic whisker movements and that serotonergic premotoneurons are part of a whisking CPG.
许多啮齿动物通过用它们的触须有节奏地触摸物体来探索周围环境。这些有节奏的触须运动（“拂动”；5-9赫兹）被认为是由一个未知的脑干中枢模式发生器（CPG）调节的。我们测试了这样一个假设，即血清素（5-羟色胺，5-HT）输入到参与拂动的面部运动神经元（wFMNs）是这个CPG的一部分。对外源性血清素的反应是，在体外记录的wFMNs以拂动频率有节奏地放电，而选择性5-HT2或5-HT3受体拮抗剂可抑制这种有节奏的放电。在体内，刺激脑干血清素能中缝核会引发触须运动。单侧注入选择性5-HT2或5-HT3受体拮抗剂会抑制同侧触须运动，并显著改变触须运动的频率和对称性。这些发现表明，血清素对于产生有节奏的触须运动既是必要的也是充分的，并且血清素能运动前神经元是拂动CPG的一部分。
