大鼠脊髓后角内神经降压素对一级传入C纤维突触前抑制效应的形态学证据(英文)

MORPHOLOGICAL EVIDENCES FOR PRESYNAPTIC INHIBITORY EFFECT OF NEUROTENSIN ON PRIMARY AFFERENT C FIBER IN THE SPINAL DORSAL HORN OF THE RAT

本研究的目的是为了揭示大鼠脊髓后角内的神经降压素是否对一级传入 C纤维进行突触前调节。荧光显微镜下观察到 ,在脊髓 ～ 层内 ,神经降压素样免疫反应性 (NTL I)的分布与来源于西非单豆素的同工凝集素 - B4( - B)的结合位点到分布有部分重叠。在共聚焦激光扫描显微镜下进一步观察显微镜下 ,在蛛网膜下腔注射辣椒素的大鼠脊髓后角浅层内 ,一些 NTL I阳性终末与变性终末形成突触性和 /或非突触性接触。以上结果表明 ,NT可通过轴轴突触和 /或非突触性轴轴接触的一级传入 C纤维的传入进行突触前抑制。此外 ,脊髓后角内还存在变性终末与含 NTL I树突形成的轴树突触。

The aim of the present study is to reveal whether neurotensin (NT) in the spinal dorsal horn of the rat might presynaptically modulate the primary afferent C fibers. With fluorescence microscope, it was observed that, in the laminae Ⅰ Ⅲ of the spinal cord, the distribution of neurotensin like immunoreactivity (NTLI) was partially overlapped with that of the binding of isolectin I B4 from Griffonia simplicifolia (I B4). The further observation with confocal laser scanning microscope showed that a few of NTLI postive terminals contacted with some I B4 labeled terminals. It was found electron microscopically in the superficial layers of the spinal cord of the rat treated with subarachnoid injection of capsaicin that NTLI containing terminals contacted with degenerated terminals with and/or without synaptic specializations. These results indicate that NT may presynaptically inhibit the transmission of primary afferent C fibers Via axoaxonic synapses and/or nonsynaptic contacts. Additionally, axodendritic synapses between degenerated terminals and NTLI containing dendrites also exist in the spinal dorsal horn.\;