Cocaine Regulation of Norepinephrine Transporter

描述(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力的各种生理过程。NE信号受多种大分子调控，包括生物合成酶、分泌蛋白、离子通道、突触前、突触后受体和NE转运体。NE信号主要通过可卡因和苯丙胺敏感的去甲肾上腺素转运体(Net)主动重新摄取儿茶酚胺而终止。已知多种生物刺激调节去甲肾上腺素信号，在心血管疾病和脑疾病中观察到去甲肾上腺素信号的改变，包括去甲肾上腺素清除和净密度。转运蛋白调节的触发因素和分子机制在控制细胞外去甲肾上腺素浓度，从而控制去甲肾上腺素信号转导中起重要作用。Net也在胎盘中表达。这增加了一种可能性，即与母亲使用精神刺激药物有关的既定医疗并发症可能部分是由于阻断了胎盘网而产生的。原代细胞培养提供了体外实验的便利，结合了天然细胞系统的真实性来研究转运蛋白调节的分子机制，更接近于体内动物模型。为了探索心理刺激剂对Net调节通路的影响，我们发展了表达内源性Net的胎盘滋养层细胞的原代培养。利用滋养层细胞培养，我们发现Net的功能和表达受到1)可卡因处理，2)受体调节，3)S激活的调节。综上所述，这些初步发现支持拟议的实验，以测试一个特定的假设，即可卡因通过可卡因对网络和/或其他细胞靶点的影响而导致的细胞机制改变，来调节网络功能和表达。本申请中提出的研究将确定可卡因调节自然网络功能和表达的机制。这些研究的结果将为我们理解滥用药物在调节网络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.