BLOOD/BRAIN BARRIER AND LEPTIN TRANSPORT IN OBESITY

描述：（申请人摘要）瘦素，一种外周产生的 多肽，在穿过血脑屏障后导致体重减轻 (BBB)进入大脑，在那里它被认为是发挥主要作用， 肥胖的调节功能。奇怪的是，在肥胖症中， 的瘦素增加，导致所谓的“瘦素 抵抗，”伴随着相对较低的瘦素水平， 脑脊液（CSF）。有人建议，该机制 引起这种“抵抗”的是瘦素通过血脑屏障的减少 通过我们在非肥胖动物中描述的运输系统。在这里， 我们将使用成熟的技术来确定 瘦素在啮齿类动物血脑屏障中转运的药代动力学 饮食性遗传性和病变性肥胖量化将涉及 多次回归分析和灌注。HPLC将确保 进入大脑的物质是完整的，毛细血管耗尽， 洗脱，将确保瘦素不保持结合到 内皮细胞将共同注射白蛋白，以纠正渗漏和非渗漏。 具体通道。饱和性，运输的自我抑制，将 用未标记的瘦素测定。定量放射自显影 图像分析将确定肥胖动物的定位位点 瘦素转运蛋白，将被分离和鉴定， 它们的活性（能量和离子依赖性）在大脑中测定 内皮细胞初步结果已经支持了我们的假设 瘦素通过血脑屏障的转运以某种形式减少， 肥胖症。尽管这种缺陷可能无法解释所有形式的“瘦素 肥胖症中的“抵抗”，瘦素穿过血脑屏障的运输系统 确实提供了一个适当的监管目标， 易受实验和最终治疗操纵的影响。

DESCRIPTION: (Applicant's abstract) Leptin, a peripherally produced polypeptide, causes weight loss after crossing the blood-brain barrier (BBB) to enter the brain where it is considered to exert a major regulatory function in obesity. Paradoxically, in obesity blood levels of leptin are increased, resulting in what has been called "leptin resistance," accompanied by relatively low levels of leptin in the cerebrospinal fluid (CSF). It has been proposed that the mechanism causing this "resistance" is decreased passage of leptin across the BBB by the transport system we have described in non-obese animals. Here, we shall use well-established techniques to determine the pharmacokinetics of the transport of leptin across the BBB in rodents with dietary, genetic, and lesioned obesity. Quantification will involve multiple-time regression analysis and perfusion. HPLC will ensure that the material entering the brain is intact and capillary depletion, with washout, will ensure that leptin does not remain bound to the endothelium. Albumin will be co-injected to correct for leakage and non- specific passage. Saturability, the self-inhibition of transport, will be determined with unlabeled leptin. Autoradiography with quantitative image analysis will determine in obese animals the sites of localization of the leptin transporters, which will be isolated and identified, and their activity (energy and ion dependence) determined in cerebral endothelia cells. Preliminary results already support our hypothesis that the transport of leptin across the BBB is decreased in some forms of obesity. Although this defect might not explain all forms of "leptin resistance" in obesity, the transport system for leptin across the BBB does provide an appropriate target of regulatory control that is susceptible to experimental and eventual therapeutic manipulation.