Attenuation of cardiac parasympathetic nerve acetylcholine release in obesity by

描述（由申请人提供）：肥胖可导致多种心血管疾病，包括高血压和左心室肥厚。此外，肥胖患者心率和血浆儿茶酚胺增加以及心率变异性降低是由于心脏自主神经控制的改变，包括交感神经活动增加和副交感神经活动减少。异常的自主驱动是高血压和充血性心力衰竭的诱因，同样也可能促进肥胖的心血管紊乱。心内交感神经末梢释放的神经肽，如神经肽Y （NPY）和甘丙肽，可抑制邻近副交感神经释放乙酰胆碱。因此，肥胖增加的交感驱动可能增加心房神经的神经肽释放，从而促进副交感神经末梢乙酰胆碱释放的抑制。本研究探讨了交感神经肽在饮食诱导的肥胖倾向大鼠心脏中抑制副交感神经递质乙酰胆碱的短期释放和长期合成中的作用。心房外植体系统将用于刺激心房末端的神经递质和神经肽的释放，这些蛋白质将用高效液相色谱-质谱法测量。开发一种基于非放射性的，灵敏的同时测量神经递质和神经肽绝对水平的检测方法，是一种重要的新方法，将通过本研究建立。我们还将在体内共同刺激自主神经外周流出，以检查肥胖副交感神经紊乱的功能后果。激光捕获心脏副交感神经节神经元显微解剖，然后进行qRT-PCR，将允许检查肥胖的胆碱能标记基因。将培养的心脏神经节神经元的神经肽受体基因敲除，以检测神经肽对乙酰胆碱合成和转运的调节。副交感神经功能减弱可导致心率控制失调，心律失常的可能性，并间接导致儿茶酚胺毒性和工作量增加引起的心肌功能障碍。这些研究应该确定新的神经肽靶点，以逆转肥胖受试者的异常副交感神经活动。此外，将开发一种灵敏的高效液相色谱-质谱同时测定神经化学物质的方法。

DESCRIPTION (provided by applicant): Obesity can lead to several cardiovascular problems including hypertension and left ventricular hypertrophy. In addition, increased heart rate and plasma catecholamines, and reduced heart rate variability in obesity are due to altered cardiac autonomic control including increased sympathetic and reduced parasympathetic, activity. Abnormal autonomic drive is a causal factor in hypertension and congestive heart failure, and may similarly promote cardiovascular disturbances in obesity. Neuropeptides such as neuropeptide Y (NPY) and galanin, released from sympathetic terminals in the heart, can inhibit acetylcholine release from adjacent parasympathetic nerves. Increased sympathetic drive in obesity may therefore augment neuropeptide release from atrial nerves, thereby promoting the inhibition of acetylcholine release from parasympathetic terminals. This study examines the role of sympathetic neuropeptides in inhibiting both short-term release, and long-term synthesis, of the parasympathetic neurotransmitter acetylcholine in the diet-induced obesity-prone rat heart. An atrial explant system will be utilized to stimulate release of neurotransmitters and neuropeptides from atrial terminals and these proteins will be measured with a sensitive HPLC-MS method. The development of a non-radioactivity based, sensitive assay for simultaneous measurements of absolute levels of neurotransmitters and neuropeptides, is an important novel approach that will be established through this study. We will also co-stimulate autonomic peripheral outflow in vivo to examine functional consequences of parasympathetic disturbances in obesity. Laser capture microdissection of parasympathetic cardiac ganglion neurons followed by qRT-PCR will allow examination of cholinergic marker genes in obesity. Cultured cardiac ganglion neurons will have neuropeptide receptor genes knocked down to examine neuropeptide regulation of acetylcholine synthesis and transport. Attenuated parasympathetic function can result in dysregulated heart rate control, potential for arrhythmias and indirectly contribute to myocardial dysfunction from catecholamine toxicity and increased workload. These studies should identify novel neuropeptide targets for reversing abnormal parasympathetic activity in obese subjects. In addition, a sensitive HPLC-MS method for simultaneous determination of neurochemicals will be developed.