Rasband M N, Park E W, Vanderah T W, Lai J, Porreca F, Trimmer J S
Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, NY 11794, USA.
Proc Natl Acad Sci U S A. 2001 Nov 6;98(23):13373-8. doi: 10.1073/pnas.231376298.
Differential expression of ion channels contributes functional diversity to sensory neuron signaling. We find nerve injury induced by the Chung model of neuropathic pain leads to striking reductions in voltage-gated K(+) (Kv) channel subunit expression in dorsal root ganglia (DRG) neurons, suggesting a potential molecular mechanism for hyperexcitability of injured nerves. Moreover, specific classes of DRG neurons express distinct Kv channel subunit combinations. Importantly, Kv1.4 is the sole Kv1 alpha subunit expressed in smaller diameter neurons, suggesting that homomeric Kv1.4 channels predominate in A delta and C fibers arising from these cells. These neurons are presumably nociceptors, because they also express the VR-1 capsaicin receptor, calcitonin gene-related peptide, and/or Na(+) channel SNS/PN3/Nav1.8. In contrast, larger diameter neurons associated with mechanoreception and proprioception express high levels of Kv1.1 and Kv1.2 without Kv1.4 or other Kv1 alpha subunits, suggesting that heteromers of these subunits predominate on large, myelinated afferent axons that extend from these cells.
离子通道的差异表达为感觉神经元信号传导带来功能多样性。我们发现，由神经性疼痛的Chung模型诱导的神经损伤会导致背根神经节（DRG）神经元中电压门控钾离子（Kv）通道亚基表达显著降低，这提示了受损神经兴奋性过高的潜在分子机制。此外，特定类型的DRG神经元表达不同的Kv通道亚基组合。重要的是，Kv1.4是在较小直径神经元中表达的唯一Kv1α亚基，这表明同型Kv1.4通道在源自这些细胞的Aδ纤维和C纤维中占主导地位。这些神经元可能是伤害感受器，因为它们还表达VR-1辣椒素受体、降钙素基因相关肽和/或钠离子通道SNS/PN3/Nav1.8。相比之下，与机械感受和本体感受相关的较大直径神经元表达高水平的Kv1.1和Kv1.2，而不表达Kv1.4或其他Kv1α亚基，这表明这些亚基的异源二聚体在从这些细胞延伸出的大的有髓传入轴突上占主导地位。
