MAXADILAN, A CUTANEOUS VASODILATOR FROM SAND FLIES

Maxadilan是已知的最有效的血管扩张剂。它是一种新的多肽 最近从沙蝇Lutzmyia的唾液腺中分离到 一种传播原生动物利什曼病的媒介。在这 建议，研究的目标是寻找Maxadilan的受体， 检测该多肽的药理作用，并对其进行表征 它的结构和功能域。 Maxadilan的受体似乎位于血管平滑肌细胞上 初步研究表明，Maxadilan提高了cAMP水平 在这些牢房里。这一秒细胞内水平的提升 信使可能是G蛋白偶联激活的结果 美沙地兰的受体。这种受体可能在 血管张力的生理调节，但不太可能 该受体的内源性配体是 不知道。兔主动脉和A细胞来源的c DNA文库的表达 Maxadilan结合的细胞系，将在COS细胞中进行 以获得编码Maxadilan受体的基因。受体 分布将通过探测来自不同地区的北方斑点来确定 在皮肤放射自显影时使用受体探针的组织 放射性标记的Maxadilan将允许受体的微定位。 药理学研究的目的是检查麦克沙地兰对心脏的影响 经典的血管平滑肌制剂和定义的第二种 被这种多肽刺激的信使途径。各种药理作用 药物包括通道阻滞剂和受体阻滞剂。容量 改变第二信使水平的Maxadilan将于#年确定 通过以下方法选择血管平滑肌制剂或培养细胞 CAMP和cGMP水平的放射免疫测定，钙通量的测量，以及 基于高效液相色谱法的放射性标记肌醇磷酸盐的检测。 将通过以下方法研究Maxadilan的结构和功能结构域 产生抗肽的单抗，表达改变的形式 用重组技术对多肽进行重组并确定其结构 用二维核磁共振技术对麦克沙地兰进行研究。 这个实验室的长期目标是利用这些机制 节肢动物通过它成功地获取血液。压倒一切的概念 一种有机体(节肢动物)可以被检查出特定的功能 (吸血)导致新蛋白质的发现(Maxadilan)和 基因。这些蛋白质和基因将提供新的工具，用于 研究血液学和心血管药理学，将带来新的 治疗剂。

Maxadilan is the most potent vasodilator known. It is a novel peptide recently isolated from salivary glands of the sand fly Lutzomyia longipalpis, a vector of the protozoan disease leishmaniasis. In this proposal, studies are directed at finding the receptor for maxadilan, examining the pharmacologic actions of this peptide, and characterizing its structural and functional domains. The receptor for maxadilan appears to be on vascular smooth muscle cells and preliminary studies suggest that maxadilan raises the level of cAMP in these cells. Elevation in the intracellular level of this second messenger probably results from the activation of G-protein coupled receptor by maxadilan. This receptor may be important in the physiological regulation of blood vessel tone but is unlikely to have been described previously and the endogenous ligand for this receptor is not known. Expression of cDNA libraries derived from rabbit aorta or a cell line to which maxadilan binds, will be performed in COS cells in order to obtain the gene encoding the maxadilan receptor. Receptor distribution will be determined by probing northern blots from various tissues with the receptor probe while autoradiography of skin probed with radiolabelled maxadilan will allow for microlocalization of the receptor. Pharmacology studies are designed to examine the effect of maxadilan on classical vascular smooth muscle preparations and define the second messenger pathway stimulated by this peptide. The various pharmacologic agents including channel blockers and receptor blockers. The capacity of maxadilan to alter second messenger levels will be determined in selected vascular smooth muscle preparations or cultured cells by radioimmunoassay of cAMP and cGMP levels, calcium flux measurements, and the HPLC-based detection of radiolabeled inositol phosphates. Structural and functional domains of maxadilan will be studied by generating monoclonal antibodies to the peptide, expressing altered forms of the peptide with recombinant techniques and determining the structure of maxadilan by 2-dimensional nuclear magnetic resonance. The long-term objectives of this laboratory are to exploit the mechanisms by which arthropods successfully obtain blood. The overriding concept is that an organism (arthropod) can be examined for a particular function (blood-feeding) leading to discovery of novel proteins (maxadilan) and genes. Such proteins and genes will provide new tools with which to study hematologic and cardiovascular pharmacology and will lead to new therapeutic agents.