Burstein R, Falkowsky O, Borsook D, Strassman A
Department of Anesthesia and Critical Care, Beth Israel Hospital, Boston, Massachusetts 02115, USA.
J Comp Neurol. 1996 Sep 30;373(4):549-74. doi: 10.1002/(SICI)1096-9861(19960930)373:4<549::AID-CNE6>3.0.CO;2-1.
We recently described a direct nociceptive projection from the spinal cord to the hypothalamus in the rat. Several electrophysiological studies of this projection indicated that the axons of some spinohypothalamic tract neurons (SHT) reach the hypothalamus either by a lateral or by a medial route. The purpose of this study was to determine the origin of all SHT neurons that reach the hypothalamus through the lateral and the medial projections, and to investigate the possibility of ablating the SHT without damaging other important sensory and motor tracts by combining retrograde tracing techniques with axonal ablation. As compared with control cases, significant (P < .05) reductions in the number of labeled SHT neurons were encountered, 26% in the ipsilateral spinal cord following lesions of the medial projection, 67% in the contralateral spinal cord following lesions of the lateral projection, and 94% in both contra- and ipsilateral sides following lesions of both the medial and lateral projections. Bilateral lesions of the lateral projections had no effect on the distribution of labeled neurons in the spinal cord and dorsal column nuclei following injections of Fluoro-Gold (FG) into the thalamus, and a small unilateral lesion of the lateral projection reduced the ipsilateral labeling in the motor cortex following injections of FG into the pyramidal decussation. These findings suggest that most SHT neurons ascend through the contralateral lateral projection and that less than half continue in the medial projection to the ipsilateral side. They also suggest a site that can be lesioned without affecting other ascending sensory spinal pathways.
我们最近描述了大鼠脊髓至下丘脑的直接伤害性投射。对该投射的多项电生理研究表明，一些脊髓下丘脑束神经元（SHT）的轴突通过外侧或内侧路径到达下丘脑。本研究的目的是确定所有通过外侧和内侧投射到达下丘脑的SHT神经元的起源，并通过将逆行追踪技术与轴突消融相结合，研究在不损伤其他重要感觉和运动束的情况下消融SHT的可能性。与对照病例相比，标记的SHT神经元数量显著减少（P <.05），内侧投射损伤后同侧脊髓减少26%，外侧投射损伤后对侧脊髓减少67%，内侧和外侧投射均损伤后双侧减少94%。向丘脑注射荧光金（FG）后，外侧投射的双侧损伤对脊髓和背柱核中标记神经元的分布没有影响，外侧投射的小单侧损伤减少了向锥体交叉注射FG后运动皮层的同侧标记。这些发现表明，大多数SHT神经元通过对侧外侧投射上升，不到一半的神经元继续通过内侧投射到同侧。它们还提示了一个可进行损伤而不影响其他上行感觉脊髓通路的部位。
