Real time imaging of neuronal excitation and cellular morphology of plastic synapses

目前认为，低频条件刺激A纤维后，初级传入C纤维到脊髓背角神经元的突触传递受到长时程抑制，在适当的电刺激或触觉刺激镇痛中起着重要作用。还已知的是，在应用P物质（从疼痛传导初级传入纤维释放的疼痛递质/调节剂）后，一些背角神经元的树突形态发生改变。因此，有人推测，形态学的变化可能是由痛觉过敏和/或异常性疼痛引起的，它可能是由镇痛药，如吗啡复位。本研究的目的是揭示脊髓背角神经元可塑性的性质。特别地，背角胶状质神经元兴奋的可塑性变化和神经元形态将通过使用电压敏感染料和共聚焦显微镜的光学成像方法来研究。 ...更多信息 我们已经发现，在背根中的A纤维的调节高频刺激强烈地改变了C-纤维诱发的神经元兴奋，在低活性的抑制性中间神经元含有抑制性氨基酸的促进下，和在高活性的抑制。条件性低频刺激抑制高频条件性易化的诱导和维持。用DiI微量油滴法染色，在激光扫描共聚焦显微镜下观察到胶质细胞背角神经元的树突状血管在预处理后扩张，这些结果用光学成像技术清楚地显示了背角神经元在信号传递和神经元形态上的可塑性变化，发生的条件刺激已知诱导痛觉过敏，异常性疼痛或镇痛，并强烈表明，这种可塑性可能是必不可少的诱导和传递的疼痛。少

It is now believed that the long-term depression of synaptic transmissions from primary afferent C fibers to spinal dorsal horn neurons after conditioning low-frequency stimulation of A fibers take a critical role in the analgesia by adequate electrical or tactile stimulation. It is also known that dendritic morphology of some dorsal horn neurons is altered after the application of substance P, the pain transmitter/modulator released from pain-conducting primary afferent fibers. Therefore, it has been speculated that the morphological change might be caused by hyperalgesia and/or allodynia, and that it might be reset by analgesics such as morphine. The purpose of the present research is thus to reveal the properties of neuronal plasticity in the spinal dorsal horn. Especially, plastic changes in the neuronal excitation and neuronal morphology in the substantia gelatinosa of the dorsal horn are to be studied by using optical imaging methods with voltage sensitive dyes and con-focal micr … More oscope.We have revealed that conditioning high-frequency stimulation of A fibers in the dorsal root robustly changed C-fiber-evoked neuronal excitation, a facilitation under a low activity of inhibitory interneurons containing inhibitory amino acids, and suppression at the high activity. Conditioning low-frequency stimulation inhibited the induction and maintenance of the high-frequency conditioning-induced facilitation. Dendritic varicosities of some dorsal horn neurons in the gelatinosa, stained with DiI by the micro oil-drop method and observed with a laser-scan con-focal microscope, were expanded after the application of conditioning.These results thus exhibited clearly by optical imaging techniques, plastic changes in the dorsal horn, both in the signal transmission and in the neuronal morphology, take place by the conditioning stimulations known to induce hyperalgesia, allodynia or analgesia, and strongly indicated that such plasticity might be essential for the induction and transmission of the pain. Less