Recovery of Viscerosensory Innervation From the Dorsal Root Ganglia of the Adult Rat Following Capsaicin-Induced Injury
Recovery of Viscerosensory Innervation From the Dorsal Root Ganglia of the Adult Rat Following Capsaicin-Induced Injury
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DOI：
10.1002/cne.22412
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发表时间：
2010-09-01
影响因子：
2.5
通讯作者：
Czaja, Krzysztof
中科院分区：
文献类型：
--
作者：
Gallaher, Zachary R.;Larios, Rose Marie;Czaja, Krzysztof
辣椒素是一种对 C 和 A δ 型神经元具有选择性的神经毒素。已知用辣椒素进行全身治疗可减少新生大鼠背根神经节（DRG）中的该亚群。为了更好地了解辣椒素对成人传入纤维的影响，我们检查了由腹腔注射逆行标记的 DRG 神经元。全身辣椒素治疗（125 mg/kg i.p.）后 3、30 或 60 天注射固蓝 (FB)。使用辣椒素后第 3 天和第 30 天，第 12 和第 13 胸背根神经节中的 FB 标记显着减少（分别为对照的 50% 和 35%）。然而，使用辣椒素后 60 天，逆行标记神经元的数量上升至对照的 65%。除了 FB 标记之外，我们还量化了 FB 标记神经元中 NR1（必需的 N-甲基-D-天冬氨酸受体亚基）和 Na(v)1.8（DRG 特异性钠通道）的免疫反应性，以及第 5 和第 6 腰椎 DRG 中两种蛋白的 mRNA 水平。 NR1 免疫反应性和 mRNA 表达遵循早期减少和随后部分恢复的模式，类似于 FB 标记。使用辣椒素后 3 天，Na(v)1.8 免疫反应性和 mRNA 表达下降至对照的约 50%，但在 60 天时完全恢复。这些数据有力地支持了这样的结论：成年大鼠在辣椒素引起的损伤后脊髓传入投射和信号传导发生了恢复。 J.Comp。内罗尔。 518:3529-3540, 2010。(C) 2010 Wiley-Liss, Inc.
Capsaicin is a neurotoxin selective for C- and A delta-type neurons. Systemic treatment with capsaicin is known to reduce this subpopulation in the dorsal root ganglia (DRG) of neonatal rats. To better understand the effects of capsaicin on adult afferent fibers, we examined DRG neurons retrogradely labeled by an i.p. injection of Fast Blue (FB) administered 3, 30, or 60 days after systemic capsaicin treatment (125 mg/kg i.p.). FB labeling in the 12th and 13th thoracic DRG was dramatically reduced 3 and 30 days post capsaicin (50% and 35% of control, respectively). However, the number of retrogradely labeled neurons rose to 65% of control by 60 days post capsaicin. In addition to FB labeling, we quantified the immunoreactivity of NR1, the obligatory N-methyl-D-aspartate receptor subunit, and Na(v)1.8, a DRG-specific sodium channel, in FB-labeled neurons as well as mRNA levels for both proteins in the 5th and 6th lumbar DRG. NR1 immunoreactivity and mRNA expression followed a pattern of early reduction and subsequent partial restoration similar to FB labeling. Na(v)1.8 immunoreactivity and mRNA expression dropped to approximately 50% of control at 3 days post capsaicin but completely recovered by 60 days. These data strongly support the conclusion that restoration of spinal afferent projections and signaling occurs in adult rats following capsaicin-induced damage. J. Comp. Neurol. 518:3529-3540, 2010. (C) 2010 Wiley-Liss, Inc.