Cocaine Regulation of Norepinephrine Transporter

描述（由申请人提供）：儿茶酚胺，去甲肾上腺素（NE）控制从血管收缩和心率到注意力和动机的各种生理过程。NE信号传导受到多种大分子的严格控制，包括生物合成酶、分泌蛋白、离子通道、突触前和突触后受体以及NE转运体（NET）。NE信号传导主要通过可卡因和安非他明敏感的去甲肾上腺素转运蛋白（NET）主动重摄取儿茶酚胺而终止。已知各种生物刺激物调节NE信号传导，并且在心血管疾病和脑部疾病中观察到NE信号传导的改变，包括NE清除和NET密度。转运蛋白调节的触发器和分子机制在细胞外NE浓度的控制以及因此NE信号传导中是重要的。NET也在胎盘中表达。这就提出了一种可能性，即与母亲使用精神兴奋剂药物相关的已确定的医学并发症可能部分来自于阻断胎盘NET。原代细胞培养提供了体外实验的便利，结合天然细胞系统的逼真性，以研究转运蛋白调节的分子机制，更接近体内动物模型。为了探索精神兴奋剂对NET调节通路的影响，我们开发了表达内源性NET的胎盘滋养层细胞的原代培养物。使用滋养层细胞培养物，我们表明NET功能和表达受1）可卡因处理，2）受体调节和3）激酶激活的调节。总之，这些初步研究结果支持拟议的实验，以测试一个特定的假设，可卡因调节NET功能和表达通过改变细胞机制，导致可卡因对NET和/或其他细胞靶点的影响。本申请中提出的研究将确定可卡因在调节天然NET的功能和表达中的作用机制。这些研究的结果将为我们了解滥用药物在调节NET功能和表达中的作用提供有价值的科学见解。

DESCRIPTION (provided by applicant): The catecholamine, norepinephrine (NE) governs various physiologic processes from vasoconstriction and heart rate to attention and motivation. NE signaling is tightly controlled by a diverse set of macromolecules including biosynthetic enzymes, secretory proteins, ion channels, pre- and post synaptic receptors and NE transporters (NETs). NE signaling is terminated primarily by active reuptake of the catecholamine via cocaine- and amphetamine-sensitive norepinephrine transporters (NETs). Various biologic stimuli are known to regulate NE signaling, and alterations in NE signaling including NE clearance and NET density are observed in cardiovascular diseases and brain disorders. The triggers and molecular mechanisms of transporter regulation are important in the control of extracellular NE concentrations and hence NE signaling. NETs are also expressed in the placenta. This raises the possibility that the established medical complications associated with the maternal use of psychostimulant drugs may arise in part from blocking placental NET. Primary cell cultures offer the facility of in vitro experimentation combined with the verisimilitude of a native cell system to study the molecular mechanisms of transporter regulation a step closer to in vivo animal models. To explore the effect of psychostimulants on NET regulatory pathways, we have developed primary cultures of placental trophoblasts that express endogenous NETs. Using trophoblast cell cultures, we show that NET function and expression are regulated by 1) cocaine treatment, 2) receptor modulation, and 3) kinase(s) activation. Together, these preliminary findings support the proposed experiments to test a specific hypothesis that cocaine regulates NET function and expression via altered cellular mechanisms that result from cocaine effects on NET and/or other cellular targets. The studies proposed in this application will identify the mechanisms of cocaine's action in regulating the function and expression of native NET. Results from these studies will provide valuable scientific insights to our understanding of the role of drugs of abuse in regulating NET function and expression.