Department of Physiology, Wakayama Medical University School of Medicine, Wakayama, Japan.
Am J Physiol Regul Integr Comp Physiol. 2010 Jan;298(1):R183-90. doi: 10.1152/ajpregu.00176.2009. Epub 2009 Nov 11.
Recent gene array and molecular studies have suggested that an abnormal gene expression profile of interleukin-6 (IL-6) in the nucleus tractus solitarii (NTS), a pivotal region for regulating arterial pressure, may be related to the development of neurogenic hypertension. However, the precise functional role of IL-6 in the NTS remains unknown. In the present study, we have tested whether IL-6 affects cardiovascular control at the level of the NTS. IL-6 (1, 10, and 100 fmol) was microinjected in the NTS of Wistar rats (280-350 g) under urethane anesthesia. Although the baseline levels of arterial pressure and heart rate did not change following IL-6 injections, the cardiac baroreflex in response to increased arterial pressure was dose-dependently attenuated. In addition, IL-6 (100 fmol) microinjections also attenuated l-glutamate-induced bradycardia at the level of the NTS. Immunohistochemical detection of IL-6 in naïve rats demonstrated that it was predominantly observed in neurons within the brain stem, including the NTS. These findings suggest that IL-6 within the NTS may play an important role for regulating cardiovascular control via modulation of input signals from baroreceptor afferents. Whether the abnormal gene expression of IL-6 in the NTS is associated in a causal way with hypertension remains to be resolved.
近期的基因芯片和分子研究表明，孤束核（NTS）中白细胞介素-6（IL-6）的异常基因表达谱可能与神经源性高血压的发生有关，孤束核是调节动脉血压的关键区域。然而，IL-6 在 NTS 中的确切功能作用尚不清楚。在本研究中，我们检测了 IL-6 是否会影响 NTS 水平的心血管控制。在乌拉坦麻醉下，将 IL-6（1、10 和 100 fmol）微注射到 Wistar 大鼠（280-350 g）的 NTS 中。尽管 IL-6 注射后动脉压和心率的基线水平没有改变，但对动脉压升高的心脏压力反射呈剂量依赖性减弱。此外，IL-6（100 fmol）微注射也减弱了 NTS 水平上 l-谷氨酸引起的心动过缓。在未处理的大鼠中对 IL-6 的免疫组织化学检测表明，它主要存在于包括 NTS 在内的脑干神经元中。这些发现表明，NTS 中的 IL-6 可能通过调节来自压力感受器传入的输入信号在调节心血管控制中发挥重要作用。NTS 中 IL-6 的异常基因表达是否与高血压有因果关系仍有待解决。
