College of Life Science, Shanghai University, Shanghai, China.
International Cooperation Laboratory of Molecular Medicine, Academy of Chinese Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.
Clin Exp Hypertens. 2022 Feb 17;44(2):134-145. doi: 10.1080/10641963.2021.2007942. Epub 2022 Jan 7.
The rostral ventrolateral medulla (RVLM) plays a key role in mediating the development of stress-induced hypertension (SIH). Furthermore, enhanced glutamate transport within glutamatergic neurons in the RVLM mediates pressor responses. Data from our previous studies suggest that the voltage-gated sodium channel NaV1.6 is overexpressed in neurons in the RVLM in SIH model rats and participates in the resulting elevation of blood pressure. However, previous studies have not investigated the relationship between NaV1.6 expression and glutamatergic neurons.
Here, we constructed an SIH rat model by knocking down NaV1.6 via microinjection of clustered regularly interspaced short palindromic repeats (CRISPR) guide RNA into the RVLM. Glutamate-related markers were quantified by Western blotting and immunofluorescence, and blood pressure was measured in the rats.
Our findings showed that vesicular glutamate transporter 1 (VGluT1) protein expression in the RVLM was higher in SIH rats than in Control rats, and GAD67 protein expression in SIH rats was lower than that in Control rats. Therefore, the number of VGluT1-positive neurons increased, while the number of GAD67-labeled neurons decreased after stress. After knocking down NaV1.6 expression in the RVLM, VGluT1 expression and the number of VGluT1-positive neurons decreased relative to those in SIH rats, while GAD67 protein expression and the number of GAD67-labeled neurons increased relative to those in SIH rats.
These results indicate that overexpression of NaV1.6 in the RVLM may mediate the transport and transformation of glutamate in neurons, and NaV1.6 may participate in SIH.
延髓头端腹外侧区（RVLM）在介导应激诱导性高血压（SIH）的发展中起着关键作用。此外，RVLM 中谷氨酸能神经元内谷氨酸转运增强介导升压反应。我们之前的研究数据表明，电压门控钠离子通道 NaV1.6 在 SIH 模型大鼠 RVLM 神经元中过度表达，并参与血压升高。然而，之前的研究并未探讨 NaV1.6 表达与谷氨酸能神经元之间的关系。
本研究通过将簇状规则间隔短回文重复（CRISPR）引导 RNA 微注射到 RVLM 中，构建 SIH 大鼠模型以敲低 NaV1.6。通过 Western blot 和免疫荧光定量谷氨酸相关标志物，并测量大鼠血压。
我们的研究结果表明，SIH 大鼠 RVLM 中囊泡谷氨酸转运体 1（VGluT1）蛋白表达高于对照组大鼠，而 SIH 大鼠 GAD67 蛋白表达低于对照组大鼠。因此，应激后 VGluT1 阳性神经元数量增加，而 GAD67 标记神经元数量减少。敲低 RVLM 中的 NaV1.6 表达后，与 SIH 大鼠相比，VGluT1 表达和 VGluT1 阳性神经元数量减少，而 GAD67 蛋白表达和 GAD67 标记神经元数量增加。
这些结果表明，RVLM 中 NaV1.6 的过度表达可能介导神经元中谷氨酸的转运和转化，NaV1.6 可能参与 SIH。
