MAXADILAN, A CUTANEOUS VASODILATOR FROM SAND FLIES

Maxadilan是已知最有效的血管扩张剂。 它是一种新的肽 最近从沙蝇Lutzomyia的唾液腺中分离出 longipalpis，原生动物疾病利什曼病的载体。 在这 建议，研究的目的是寻找Maxadilan的受体， 检查该肽的药理作用，并表征 其结构和功能域。 Maxadilan的受体似乎位于血管平滑肌细胞上 初步研究表明，Maxadilan可提高cAMP水平， 在这些细胞中。 在细胞内水平的升高， 信使可能是由G蛋白偶联的激活引起的。 Maxadilan的受体。 这种受体可能在 血管张力的生理调节，但不太可能具有 已经描述过，该受体的内源性配体是 不知道。 兔主动脉和动脉cDNA文库的表达 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的北方印迹来确定。 组织与受体探针，而皮肤放射自显影探测 放射性标记的Maxadilan将允许受体的微定位。 药理学研究旨在检查Maxadilan对 经典的血管平滑肌制备，并定义了第二个 由这种肽刺激的信使途径。 各种药理学 包括通道阻断剂和受体阻断剂的药物。 的能力 改变第二信使水平将在 选择的血管平滑肌制备物或培养的细胞， cAMP和cGMP水平的放射免疫测定，钙通量测量，以及 放射性标记磷酸肌醇的HPLC检测。 Maxadilan的结构和功能域将通过 产生针对所述肽的单克隆抗体， 肽的重组技术和确定结构 Maxadilan的二维核磁共振。 这个实验室的长期目标是探索 节肢动物成功获取血液的方法 最重要的概念 一个生物体（节肢动物）可以被检测出特定的功能， （血液喂养）导致发现新的蛋白质（maxadilan）， 基因. 这些蛋白质和基因将提供新的工具， 研究血液学和心血管药理学， 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.