Serotonin modulates pallidal neuronal activity in the awake monkey
Serotonin modulates pallidal neuronal activity in the awake monkey
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DOI：
10.1523/jneurosci.4058-06.2007
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发表时间：
2007-01-03
影响因子：
5.3
通讯作者：
Nambu, Atsushi
中科院分区：
文献类型：
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作者：
Kita, Hitoshi;Chiken, Satomi;Nambu, Atsushi
中缝背核含5-羟色胺（5-HT）的神经元投射到苍白球的外节和内节，表达几种5-HT受体。虽然5-HT参与了基底神经节的运动控制，但对5-HT在苍白球中的生理作用知之甚少。以往的解剖学研究和离体生理学研究表明：（1）5-HT通过突触前5-HT_（1B）受体抑制GABA能抑制作用，（2）5-HT通过突触后5-HT_（1A）受体抑制苍白球神经元放电，（3）5-HT通过突触后5-HT_（1A）受体抑制苍白球神经元放电，（4）5-HT通过突触后5-HT_（1B）受体抑制苍白球神经元放电，（5）5-HT通过突触后5-HT_（1A）受体抑制苍白球神经元放电。（3）5-HT通过激活5-HT_（2C）、5-HT_（4）或5-HT_（7）受体而突触后兴奋苍白球神经元。为了测试这些可能性，我们研究了局部应用的激动剂和拮抗剂的5-HT对自发神经元放电和苍白球神经元的兴奋性和抑制性反应，在清醒的猴子的运动皮层的电刺激的影响。虽然在体实验中还不能确定参与这种作用的受体类型或活性部位，但结果提示：（1）5-HT可能通过5-HT 1B受体强烈抑制GABA能抑制作用，（2）在苍白球外段，这种抑制作用可能涉及其他受体或机制;（3）5-HT可能通过5-HT_（1A）受体而非5-HT_（1B）受体抑制海马能兴奋。本研究没有分离或鉴定出5-HT的强烈的、直接的突触后抑制或兴奋作用的存在。因此，本研究结果表明，5-HT调制的苍白球节段的突触输入，并发挥了重要的作用，在运动控制。
Serotonin (5-HT)-containing neurons in the dorsal raphe project to the external and internal segments of the pallidum, which express several 5-HT receptors. Although the involvement of 5-HT in basal ganglia movement control has been suggested, little is known about the physiological action of 5-HT in the pallidum. Previous anatomical studies and in vitro physiological studies in other brain areas have suggested the following possibilities: (1) 5-HT suppresses GABAergic inhibition through presynaptic 5-HT1B receptors; (2) 5-HT decreases the firing of pallidal neurons through postsynaptic 5-HT1A receptors; and (3) 5-HT postsynaptically excites pallidal neurons through activation of 5-HT2C, 5-HT4, or 5-HT7 receptors. To test these possibilities, we examined the effects of locally applied agonists and antagonists of 5-HT on spontaneous neuronal firing and on excitatory and inhibitory responses of pallidal neurons to electrical stimulation of the motor cortex in awake monkeys. Although in vivo experiments could not conclusively determine the receptor types or the active sites involved in the observed effects, the results suggested the following possibilities: (1) 5-HT strongly suppresses GABAergic inhibition probably through 5-HT1B receptors; (2) in the external pallidal segment, the suppression may involve additional receptors or mechanisms; and (3) 5-HT suppresses glutamatergic excitation probably through 5-HT1A (and not 5-HT1B) receptors. The present study did not isolate or identify the existence of strong, direct postsynaptic inhibitory or excitatory effects of 5-HT. Thus, present results imply that 5-HT modulates synaptic inputs of both pallidal segments and exerts a significant role in movement control.