EDHF in the Cerebral Circulation

描述（由申请人提供）：近年来，我们和其他人已经确定，除了NO和环氧化酶代谢产物外，至少有一种内皮过程可以扩张脑血管。这个新过程被称为“内皮衍生的超极化因子”或EDHF，可能是正常生理状态和病理状态下脑循环中的重要扩张机制。在本研究中，我们将探讨EDHF在脑动脉中的作用机制。主要假设是串联孔域钾通道参与了edhf介导的大鼠脑血管扩张。为了使上述假设有效，那么以下所有具体目标必须是正确的。（特定目的1）串联孔结构域钾通道必须存在于脑动脉中；（Specific Aim 2）串联孔域钾通道的激活必须引起脑动脉的扩张，（Specific Aim 3）串联孔域钾通道的抑制必须抑制edhf介导的扩张。在Specific Aim 1中，我们计划结合RT-PCR、Western分析、免疫组织化学和电生理学来证明脑动脉中串联孔域钾通道的存在，并进一步证明它们是功能性的。在特定的Aim 2中，我们将使用孤立的灌注脑动脉来确定这些通道的激活是否会产生扩张。此外，我们计划确定通道表达的抑制（反义）和药物阻滞剂的抑制是否拮抗这些钾通道产生的扩张。在Specific Aim 3中，我们建议确定串联孔域钾通道的抑制是否会抑制edhf介导的扩张。这些研究的完成将对EDHF及其脑循环控制机制提供重要的见解。此外，我们预计有关串联孔域钾通道的新信息将是理解脑循环控制的重要一步。

DESCRIPTION (provided by applicant): ln recent years, we and others have determined that at least one endothelial process, in addition to NO and cyclooxygenase metabolites, dilates cerebral vessels. This new process, termed "endothelium-derived hyperpolarizing factor" or EDHF, is likely an important dilator mechanism in the cerebral circulation during normal physiological states and following pathological conditions. In the proposed studies, we will address the mechanism of EDHF in cerebral arteries. The major hypothesis to be tested is that tandem-pore domain potassium channels are involved with the EDHF-mediated dilations in cerebral vessels of the rat. In order for the above hypothesis to be valid then all of the following specific aims must be true. (Specific Aim 1) Tandem-pore domain potassium channels must be present in cerebral arteries; (Specific Aim 2) activation of tandem-pore domain potassium channels must elicit dilation in cerebral arteries, and (Specific Aim 3) inhibition of tandem-pore domain potassium channels must inhibit EDHF-mediated dilations. In Specific Aim 1, we plan to use a combination of RT-PCR, Western analysis, immunohistochemistry, and electrophysiology to demonstrate the presence of the tandem pore domain potassium channels in cerebral arteries and, further, demonstrate that they are functional. In specific Aim 2, we will use isolated perfused cerebral arteries to determine if activation of these channels produces dilation. Furthermore, we plan to determine if inhibition of channel expression (anti-sense) and inhibition by pharmacological blockers antagonizes dilations produced by these potassium channels. In Specific Aim 3, we propose to determine if inhibition of tandem pore domain potassium channels inhibit EDHF-mediated dilations. Completion of the proposed studies will provide important insight into EDHF and its mechanism of circulatory control in brain. Furthermore, we anticipate that new information regarding tandem pore domain potassium channels will be a big step in the understanding of cerebral circulatory control.