VASCULAR SMOOTH MUSCLE PLASTICITY IN NITRIC OXIDE

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。高血压和血管内皮细胞功能受损对血管收缩的影响尚不完全清楚，尤其是可能发生的分子变化。我们正在研究一氧化氮缺乏和高血压对平滑肌离子通道表达谱的影响。大鼠饮用含有NW-硝基-L-精氨酸的水14天，以抑制一氧化氮的产生，并导致高血压。高血压损害内皮依赖的松弛，增强血管收缩。高血压可使肌膜电位去极化，这可能是收缩增加的基础；然而，相关机制尚不清楚。我们正在验证一种假设，即高血压降低了正常调节膜电位的血管平滑肌离子通道的分子和功能表达。RT-PCR、Western印迹和膜片钳电生理技术被用来在基因、蛋白质和功能水平上评估离子通道的表达。我们的数据表明，高血压降低了至少两种主要类型的钾通道的分子和功能表达：钙激活的钾通道和电压依赖的钾通道。钙激活的K+通道BKα亚单位蛋白的表达减少。此外，这与钙激活的K+电流减少有关。电压依赖性K+通道Kv1.5蛋白表达减少。这也得到了降低的电压依赖性K+电流的支持。这些发现提示，平滑肌K+通道分子和功能表达减少可能导致去极化，增强收缩，并参与高血压的发病机制。我们目前正在努力确定控制这些K+通道表达变化的分子机制。这个实验室在解决这一假设方面具有得天独厚的优势，Cobre赠款允许机会、资源和基础设施确保项目和人员的发展。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Effects of hypertension and impaired vascular endothelial function on smooth muscle contraction are not completely understood; particularly what molecular changes may take place. We are investigating the effects of nitric oxide deficiency and hypertension on the expression profile of ion channels in smooth muscle. Rats drink water containing Nw-nitro-L-arginine for 14 days to inhibit nitric oxide production and cause hypertension. Hypertension impairs endothelium-dependent relaxation and augments smooth muscle contraction. Smooth muscle membrane potential is depolarized by hypertension and may be the basis for increased contraction; however, mechanisms responsible are not known. We are testing the hypothesis that hypertension decreases the molecular and functional expression of ion channels in vascular smooth muscle that normally regulate membrane potential. RT-PCR, Western blot, and patch clamp electrophysiology techniques are used to assess ion channel expression at the gene, protein, and functional level. Our data indicate that hypertension decreases molecular and functional expression at least two major types of potassium channels: Ca2+-activated and voltage-dependent K+ channels. Expression of the BK alpha subunit protein, a Ca2+-activated K+ channel, is reduced. Further, this correlates with reduced Ca2+-activated K+ current. Expression of Kv1.5 protein, a voltage-dependent K+ channel, is reduced. This is also supported by reduced voltage-dependent K+ current. These findings suggest that reduced molecular and functional expression of smooth muscle K+ channels may lead to depolarization, augmented contraction, and contribute to the pathogenesis of hypertension. We are currently directing our efforts at determining molecular mechanisms governing these changes in K+ channel expression. This laboratory is uniquely positioned to address the hypothesis and the COBRE grant allows opportunities, resources, and infrastructure to ensure the development of the project and personnel.