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Identification and characterization of enkephalinergic neurons in spinal cord dorsal horn: Single cell RT-PCR analysis

脊髓背角脑啡肽能神经元的鉴定和表征：单细胞 RT-PCR 分析

基本信息

批准号：
09680818
负责人：
HORI Yuuichi
金额：
$ 0.64万
依托单位：
Dokkyo University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

1. We adapted the technique of single-cell reverse transcription- polymerase chain reaction (RT-PCR) for small neurons in the superficial dorsal horn of rat spinal cord slices. Nethionin-enkephalin sequence-specific PCR products were observed in more than half of superficial dorsal horn neurons studied. This is reminiscent of the previous immunohistochemical reports that a high density of enkephalin neurons are present in the superficial dorsal horn2. Under current clamp conditions, depolarizing current injection stimulated dorsal horn neurons to generate spikes. Characteristically, enkephalinergic neurons usually displayed marked spike accommodation with a progressive prolongation of interspike intervals. In addition, enkephalinergic neurons seldom showed an initial sag upon hyperpolarizing current injection, indicating enkephalinergic neurons lack a time-dependent inwardly rectifying channel.3. Under voltage clamp conditions, ionic currents evoked by voltage command was investigated. The following potassium currents were observed in enkephalinergic neurons: transient IA currents (in 39 of 46 enkephalinergic neurones studied); Inward rectifier ( in 18 of 39); Ca2+-dependent potassium currents (in 14 of 31); and delayed rectifier (in all enkephalinergic neurones studied).4. Barbiturates hyperpolarized enkephalinergic neurons and suppressed spike generation in response to depolarizing currents injection.5. It was also found that mRNA of 5-HT3 receptors was detected in some 40% of enkephalin-containing neurons. It is strongly suggested that enkephalinergic inhibitory neurons mediate Serotonin-induced spinal analgesia, owing at least partly to activation of 5-HT3 receptors expressed in enkephalinergic neurons.

1.采用单细胞逆转录-聚合酶链反应（RT-PCR）技术，对大鼠脊髓片背角浅层小神经元进行了研究。在超过一半的浅层背角神经元研究中观察到脑啡肽序列特异性PCR产物。这让人想起以前的免疫组织化学报告，高密度的脑啡肽神经元存在于浅背角2。在电流钳条件下，去极化电流刺激背角神经元产生锋电位。特征性地，脑啡肽能神经元通常表现出明显的峰电位调节，峰电位间期逐渐延长。此外，脑啡肽能神经元在注入超极化电流后很少出现初始凹陷，表明脑啡肽能神经元缺乏时间依赖性内向整流通道.在电压钳条件下，研究了电压指令诱发的离子电流。在脑啡肽能神经元中观察到以下钾电流：瞬时IA电流（在所研究的46个脑啡肽能神经元中的39个）;内向整流电流（在39个脑啡肽能神经元中的18个）; Ca 2+依赖性钾电流（在31个脑啡肽能神经元中的14个）;和延迟整流电流（在所研究的所有脑啡肽能神经元中）.巴比妥类药物可使脑啡肽能神经元超极化，抑制去极化电流诱发的放电.在含脑啡肽的神经元中，约40%的神经元含有5-HT_3受体的mRNA。这强烈表明，脑啡肽能抑制神经元介导的5-羟色胺诱导的脊髓镇痛，至少部分是由于脑啡肽能神经元中表达的5-HT 3受体的激活。