The role of the M-current in the anorectic effects of estrogen and serotonin.

描述（由申请人提供）：拟议研究的长期目标是了解雌激素如何通过控制下丘脑神经元中钾通道基因表达或通过与其他神经递质（如5-羟色胺）协同改变神经元兴奋性来影响能量稳态。雌激素是导致食物摄入量和体重减少的厌食剂，并且已知雌激素能增强雌激素能药物的厌食作用。雌激素和5-羟色胺的厌食作用的一个潜在机制是抑制POMC神经元中的M-电流。为了确定M-电流是否在这些效应中起作用，将在弓状核中使用qRT-PCR在雌激素处理后确定KCNQ亚基（2、3和5）的表达变化，所述KCNQ亚基形成负责脑中M-电流的异多聚体通道，以及它们的信号传导调节剂。将使用单细胞RT-PCR来确定KCNQ亚基的分布模式以及与细胞类型标志物（POMC、NPY）的共定位。将使用来自油和雌激素处理的动物的POMC和NPY神经元的全细胞斑片记录来检查雌激素预处理对弓状神经元中M电流的电生理学特性的影响。记录还将通过使用毒蕈碱受体激动剂和选择性5 HT 2C受体激动剂的M-电流衰减来确定通过推定的雌激素膜受体对雌激素的快速反应对M-电流的任何直接调节。5-羟色胺对食物摄入的抑制可能涉及通过5 HT 2C受体调节M电流。将5 HT 2C受体激动剂注射（icv）到用油或雌激素处理的卵巢切除小鼠中。在注射选择性5 HT 2CR激动剂（含或不含M-电流药理学调节剂）后48小时测量体重和摄食量。如果M电流的调节对于5-羟色胺或雌激素调节食物摄入是重要的，则M电流激活剂应部分或完全减弱5-羟色胺和/或雌激素的厌食作用。肥胖是发达国家青少年和成人面临的主要健康问题之一，几乎没有安全的治疗药物可用于帮助人群保持健康的体重。必须检查外周和中枢信号控制食物摄入的机制，以制定新的策略和治疗方法来解决我们今天面临的最严重的健康问题之一。

DESCRIPTION (provided by applicant): The long range goal of the proposed research is to understand how estrogen affects energy homeostasis either through controlling potassium channel gene expression in hypothalamic neurons or by synergistically altering neuronal excitability with other neurotransmitters such as serotonin. Estrogens are anorectic leading to decreased food intake and body weight and are known to potentiate the anorectic effects of serotonergic drugs. One potential mechanism for the anorectic effects of estrogen and serotonin is inhibition of the M- current in POMC neurons. In order to determine if the M-current plays a role in these effects, changes in expression of KCNQ subunits (2, 3, & 5), which form the heteromultimeric channels responsible for the M- current in the brain, and their signaling modulators will be determined following estrogen treatment in the arcuate nucleus using qRT-PCR. Single cell RT-PCR will be used to determine the distribution pattern of KCNQ subunits and co-localization with cell type markers (POMC, NPY). The effects of estrogen pre- treatment on the electrophysiological properties of the M-current in arcuate neurons will be examined using whole cell patch recordings of POMC and NPY neurons from oil and estrogen-treated animals. Recordings will also determine any direct modulation of the M-current via a rapid response to estrogen through the putative estrogen membrane receptor using the M-current attenuation by a muscarinic receptor agonist and a selective 5HT2C receptor agonist. The inhibition of food intake by serotonin may involve modulation of the M-current through 5HT2C receptors. Agonist of the 5HT2C receptor will injected (icv) into ovariectomized mice treated with oil or estrogen. Weight and food intake will be measured for 48 hr after injection of a selective 5HT2CR agonist with or without pharmacological modulators of the M-current. If the modulation of the M current is important for the regulation of food intake by either serotonin or estrogen, the M-current activator should partially or completely attenuate the anorectic effects of 5HT and/or estrogen. Obesity is one of the major health issues facing the adolescents and adults in the developed world with few safe therapeutic drugs available to assist the population in maintaining a healthy weight. The mechanism through which peripheral and central signals control food intake must be examined to develop new strategies and therapies for one of the most serious health issues facing us today.