Serotonin, nitric oxide and histamine enhance the excitability of neuron MCC by diverse mechanisms
Serotonin, nitric oxide and histamine enhance the excitability of neuron MCC by diverse mechanisms
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DOI：
10.1556/abiol.55.2004.1-4.25
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发表时间：
2004-01-01
影响因子：
--
通讯作者：
Tieman, D
中科院分区：
文献类型：
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作者：
Jacklet, J;Grizzaffi, J;Tieman, D
血清素、一氧化氮 (NO) 和组胺是软体动物神经系统中使用的神经调节剂。我们发现它们中的每一种都会去极化并增加海兔的血清素供给神经回路调节器神经元（MCC）的兴奋性，但每种都会引起背景离子电流的不同变化并使用不同的第二信使。使用 NO 和组胺刺激大脑神经节中的神经元 C2 可诱导 MCC 中的 vsEPSP。当这些神经元在培养物中被分离时，它们会形成介导 vsEPSP 的突触。在分离培养的 MCC 中研究了这些神经调节剂诱导的离子电流。组胺降低了 -70 至 -30 mV 之间的背景外向电流，该电流被钴处理所阻断，表明它是钙激活的钾电流。血清素将背景外向电流从-65 mV降低至-30 mV，并增强钾内向电流，其负值比被铯和钡阻挡的-70 mV更负。 8-Br-cAMP 模仿了这种反应。 NO 供体将钴不敏感的背景外向电流降低至 -70 至 -30 mV 之间。8-Br-cGMP 模仿了该反应。这些反应表明 MCC 在调节喂养神经回路期间可以产生复杂的时间和状态依赖性活动。
Serotonin, nitric oxide (NO) and histamine are neuromodulators used in molluscan nervous systems. We have found that each of them depolarizes and increases the excitability of the serotonergic feeding neural circuit modulator neuron, MCC, of Aplysia, but each induces different changes in background ionic currents and uses a different second messenger. Stimulation of neuron C2 in the cerebral ganglion induces a vsEPSP in MCC using NO and histamine. When these neurons are isolated in culture they form synapses that mediate the vsEPSP. The ionic currents induced by these neuromodulators were investigated in isolated cultured MCCs. Histamine reduced a background outward current between -70 and -30 mV that was blocked by cobalt treatment, indicating that it is a calcium activated potassium current. Serotonin reduced a background outward current from -65 mV to -30 mV and enhanced a potassium inward current more negative than -70 mV that was blocked by cesium and barium. This response was mimicked by 8-Br-cAMP. NO donors reduced a cobalt insensitive background outward current between -70 and -30 mV This response was mimicked by 8-Br-cGMP. These responses show that MCC can produce complex time and state-dependent activity during its modulation of the feeding neural circuit.