LOCAL ANESTHETICS--RECEPTOR TOPOLOGY AND DRUG DESIGN

描述：（改编自申请人的摘要） 建议是（1）绘制局部麻醉剂（LA）受体的拓扑结构 在电压门控Na+通道中，（2）设计更好的Na+通道阻断剂 对这种LA受体，和（3）利用这些阻断剂在体内作为 长效乳酸菌 镧系化合物及其季铵盐的推定受体 (QA)衍生物已被分配在电压门控的a亚基内， Na+通道。 这种推定的LA受体上的各种氨基酸残基将 通过定点诱变方法进行突变。 突变体和野生型 大鼠mu 1克隆的肌肉Na+通道将瞬时表达 转染的哺乳动物细胞，以及它们与常规LA和新LA的结合。 合成的QA药物将在贴片膜和/或平面膜中进行评估。 脂质双层在单通道水平与蛙毒素存在。 的 与药物的结合接触将在LA受体内绘制。 他们 还将继续设计一系列来自各种LA的QA衍生产品; 所用的LA包括托卡因、普鲁卡因、丁卡因和依替卡因。 这些 高亲和力Na+通道阻滞剂，反过来，将被用来解决 进一步研究LA受体的拓扑结构。 新合成的药物将被 首先在体外测试它们在天然Na+通道中的结合亲和力 以及随后在体内用于它们在大鼠坐骨神经阻滞中的功效， 大鼠脊髓阻滞。 N-丁基丁卡因及其相关QA衍生物， 将坐骨神经感觉和运动功能阻断一周以上 检查其局部麻醉和神经损伤特征。 破坏神经纤维但保留组织的神经破坏性化合物 然后将探索后期神经再生的完整性作为潜在的 超长效局部麻醉剂 总之，这些实验 我们在分子水平上对LA受体有了更清晰的认识， 为我们提供了更好的钠通道阻滞剂和更长的阻滞时间。 这些 高亲和力Na+通道阻滞剂可能对患有 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.