Carstens Earl E, Carstens Mirela Iodi, Simons Christopher T, Jinks Steven L
Department of Neurobiology, Physiology and Behavior, University of California, Davis1 Shields Avenue, Davis, CA 95616, USA.
Neuroreport. 2010 Mar 10;21(4):303-8. doi: 10.1097/WNR.0b013e328337310a.
Itch is thought to be signaled by pruritogen-responsive neurons in the superficial spinal dorsal horn. Many neurons here express the substance P NK-1 receptor. We investigated whether neurotoxic destruction of spinal NK-1-expressing neurons affected itch-related scratching behavior. Rats received intracisternal substance P conjugated to saporin (SP-SAP), or saporin (SAP) only (controls), and were subsequently tested for scratching behavior elicited by intradermal 5-hydroxytryptamine. SAP controls exhibited dose-related hindlimb scratching, which was significantly attenuated in SP-SAP-treated rats. There was a virtual absence of NK-1 immunoreactive neurons in superficial laminae of the upper cervical and medullary dorsal horn in SP-SAP-treated rats. These results indicate that superficial dorsal horn neurons expressing NK-1 receptors play a key role in spinal itch transmission.
瘙痒被认为是由脊髓背角浅层中对致痒原产生反应的神经元发出信号的。这里的许多神经元表达P物质NK-1受体。我们研究了脊髓中表达NK-1的神经元的神经毒性破坏是否会影响与瘙痒相关的抓挠行为。给大鼠脑池内注射与皂草素结合的P物质（SP-SAP），或仅注射皂草素（SAP，作为对照），随后测试皮内注射5-羟色胺引发的抓挠行为。SAP对照组表现出与剂量相关的后肢抓挠，而在接受SP-SAP治疗的大鼠中这种抓挠明显减弱。在接受SP-SAP治疗的大鼠的上颈髓和延髓背角浅层中，几乎没有NK-1免疫反应性神经元。这些结果表明，表达NK-1受体的脊髓背角浅层神经元在脊髓瘙痒传递中起关键作用。
