LOCAL ANESTHETICS--RECEPTOR TOPOLOGY AND DRUG DESIGN

描述：(改编自申请者的摘要)这项活动的目标 建议：(1)绘制局麻药(LA)受体的拓扑图 在电压门控钠离子通道中，(2)设计更好的钠离子通道阻滞剂 与该LA受体结合，以及(3)在体内利用这些阻滞剂作为 长期发挥作用的拉斯维加斯。LAS的可能受体及其季铵盐 (QA)导数已在电压门控的a-子单元内分配 Na+通道。这个推测的LA受体上的各种氨基酸残基将 用定点诱变的方法进行突变。突变体和野生型 大鼠MU1克隆的肌肉Na+通道将瞬时表达 转基因哺乳动物细胞及其与常规LAS和新细胞的结合 合成的QA药物将在贴片膜和/或平面上进行评估 在含有巴曲霉毒素的单通道水平上存在脂双层。这个 与药物的结合接触将被绘制在LA受体内。他们 还将继续从各种LAS中设计一系列QA衍生品； 使用的LAS包括托尼卡因、普鲁卡因、丁卡因和伊多卡因。这些 高亲和力的钠离子通道阻滞剂又将被用来解决 此外，LA受体的拓扑结构。新合成的药物将是 首次在体外测试它们与天然钠离子通道的结合亲和力 并随后在体内观察其对大鼠坐骨神经阻滞和 在大鼠脊髓阻滞中。正丁基丁卡因及其相关的QA衍生物 阻断坐骨神经感觉和运动功能一周以上 检查其局部麻醉剂和神经松解剂的特性。 破坏神经纤维但保留组织的神经溶解化合物 以后神经再生的完整性将作为潜在的探索。 超长效的局麻药。总而言之，这些实验应该会带来 我们在分子水平上对LA受体有了更清晰的认识，很可能 为我们提供更好的钠离子通道阻滞剂和更长的阻断时间。这些 高亲和力钠离子通道阻滞剂可能有益于 慢性和顽固性癌症疼痛。

DESCRIPTION: (Adapted from the applicant's abstract) The goals of this proposal are (1) to map the topology of the local anesthetic (LA) receptor in voltage-gated Na+ channels, (2) to design better Na+ channel blockers toward this LA receptor, and (3) to utilize these blockers in vivo as long-acting LAs. The putative receptor of LAs and their quaternary ammonium (QA) derivatives has been assigned within the a-subunit of the voltage-gated Na+ channel. Various amino acid residues on this putative LA receptor will be mutated by the site-directed mutagenesis method. Mutants and wild-type muscle Na+ channels of rat mu1 clones will be expressed in transiently transfected mammalian cells, and their binding to conventional LAs and newly synthesized QA drugs will be assessed in patch membranes and/or in planar lipid bilayers at the single channel level with batrachotoxin present. The binding contacts to the drugs will be charted within the LA receptor. They will also continue to design a series of QA derivatives from various LAs; among LAs used are tonicaine, procaine, tetracaine, and etidocaine. These high-affinity Na+ channel blockers, in turn, will be employed to resolve further the topology of the LA receptor. Newly synthesized drugs will be tested first in vitro for their binding affinities in native Na+ channels and subsequently in vivo for their efficacy in rat sciatic nerve block and in rat spinal block. N-butyl tetracaine and its related QA derivatives that block sciatic sensory and motor functions for more than one week will be examined for their local anesthetic and neurolytic characteristics. Neurolytic compounds that destroy nerve fibers but retain the tissue integrity for later nerve regeneration will then be explored as potential ultralong-acting local anesthetics. Together, these experiments should give us a clearer view of the LA receptor at the molecular level and likely provide us better Na+ channel blockers with longer duration of block. These high-affinity Na+ channel blockers may be beneficial for patients with chronic as well as intractable cancer pain.