Quantitation of contacts among sensory, motor, and serotonergic neurons in the pedal ganglion of aplysia.
Quantitation of contacts among sensory, motor, and serotonergic neurons in the pedal ganglion of aplysia.
复制标题
海兔足神经节中感觉、运动和血清素能神经元之间接触的定量。
DOI：
10.1101/lm.63903
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Cleary,LeonardJ
中科院分区：
文献类型：
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作者：
Zhang,Han;Wainwright,Marcy;Byrne,JohnH;Cleary,LeonardJ
目前的长期致敏模型表明，增强的行为反应是由于，至少部分是由于介导防御性退缩反射的感觉神经元的生长。据推测，这种生长通过与跟随神经元形成新的突触来加强先前存在的连接。然而，感觉运动接触的数量和连接的生理强度之间的关系从未在完整的神经节中进行过研究。作为解决这一问题的第一步，我们使用共聚焦显微镜检查幼稚动物的感觉和运动神经元之间的接触部位。我们的研究结果显示，生理上连接的细胞之间的接触相对较少。此外，接触部位的数量与直接刺激感觉神经元在跟随运动神经元中引起的EPSP的幅度成正比。这是首次在中枢神经系统中观察到这种相关性。5-羟色胺是神经递质中最密切的检查，其作用是调节突触强度的感觉运动突触。然而，神经元能过程和感觉运动突触的结构关系从未被研究过。令人惊讶的是，多巴胺能过程通常与感觉和运动神经元在距离感觉运动突触相对较远的部位接触。这一结果意味着异突触调节是由于5-羟色胺非定向释放到神经元。
Present models of long-term sensitization inAplysia californicaindicate that the enhanced behavioral response is due, at least in part, to outgrowth of sensory neurons mediating defensive withdrawal reflexes. Presumably, this outgrowth strengthens pre-existing connections by formation of newsynapses with follower neurons. However, the relationship between the number of sensorimotor contacts and the physiological strength of the connection has never been examined in intact ganglia. As a first step in addressing this issue, we used confocal microscopy to examine sites of contact between sensory and motor neurons in naive animals. Our results revealed relatively fewcontacts between physiologically connected cells. In addition, the number of contact sites was proportional to the amplitude of the EPSP elicited in the follower motor neuron by direct stimulation of the sensory neuron. This is the first time such a correlation has been observed in the central nervous system. Serotonin is the neurotransmitter most closely examined for its role in modulating synaptic strength at the sensorimotor synapse. However, the structural relationship of serotonergic processes and sensorimotor synapses has never been examined. Surprisingly, serotonergic processes usually made contact with sensory and motor neurons at sites located relatively distant from the sensorimotor synapse. This result implies that heterosynaptic regulation is due to nondirected release of serotonin into the neuropil.