Gholami Soghra, Lambertz Daniela, Hoheisel Ulrich, Mense Siegfried
Department of Basic Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
Neurosci Res. 2006 Nov;56(3):270-8. doi: 10.1016/j.neures.2006.07.004. Epub 2006 Sep 7.
Nociceptive information from skin and muscle is differently processed at many levels of the central nervous system. However, with regard to nociceptive input from muscle to the thalamus, only few data are available. Here, we investigated the c-Fos expression in the thalamus and the periaqueductal grey matter (PAG) induced by electrical stimulation of tetrodotoxin-resistant (TTX-r), presumably nociceptive, afferent fibres. In addition, a comparison between the effects of TTX-r input from muscle and skin was made. In anaesthetised rats, a skin or a muscle nerve was stimulated electrically for 1h at an intensity supramaximal for unmyelinated fibres. To block TTX-sensitive afferents, TTX was applied to the sciatic nerve. c-Fos was visualized using DAB immunohistochemistry. Here we report for the first time that in the PAG and medial thalamus, the main effect of TTX-r input from muscle was a reduction in c-Fos expression, and that in some thalamic nuclei (e.g. posterior, reuniens, and central medial nuclei), significant differences in the number of c-Fos-positive cells were found after muscle and cutaneous input, respectively. The thalamic regions with the strongest effects of muscle input were the VL bilaterally and the VPL contralaterally (increase in c-Fos expression) as well as the rhomboid nucleus (decrease in c-Fos expression).
来自皮肤和肌肉的伤害性信息在中枢神经系统的多个层面有着不同的处理方式。然而，关于从肌肉到丘脑的伤害性输入，可用的数据很少。在此，我们研究了由电刺激抗河豚毒素（TTX-r）的、推测为伤害性的传入纤维所诱导的丘脑和导水管周围灰质（PAG）中的c-Fos表达。此外，还对来自肌肉和皮肤的TTX-r输入的效应进行了比较。在麻醉大鼠中，以对无髓纤维超最大强度的电流分别电刺激皮肤或肌肉神经1小时。为阻断对TTX敏感的传入纤维，将TTX应用于坐骨神经。使用DAB免疫组织化学法观察c-Fos。在此我们首次报告，在PAG和内侧丘脑中，来自肌肉的TTX-r输入的主要效应是c-Fos表达减少，并且在一些丘脑核团（如后核、连合核和中央内侧核）中，分别在肌肉和皮肤输入后发现c-Fos阳性细胞数量存在显著差异。肌肉输入影响最强的丘脑区域是双侧的腹外侧核（VL）和对侧的腹后外侧核（VPL）（c-Fos表达增加）以及菱形核（c-Fos表达减少）。
