Attenuation of cardiac parasympathetic nerve acetylcholine release in obesity by

描述(申请人提供)：肥胖会导致几种心血管问题，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的增加和心率变异性的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。自主神经驱动异常是高血压和充血性心力衰竭的原因之一，同样可能会促进肥胖患者的心血管疾病。从心脏交感神经末梢释放的神经肽，如神经肽Y(NPY)和甘丙素，可以抑制相邻副交感神经的乙酰胆碱释放。因此，肥胖患者交感神经驱动力的增强可能会增加心房神经的神经肽释放，从而促进副交感神经末梢的乙酰胆碱释放的抑制。本研究检测交感神经肽在抑制饮食诱导的肥胖倾向大鼠心脏中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。将利用心房外植体系统刺激从心房末端释放神经递质和神经肽，并用灵敏的高效液相色谱-质谱法测定这些蛋白质。开发一种非放射性的、灵敏的同时测量神经递质和神经肽绝对水平的分析方法，是通过这项研究建立的一种重要的新方法。我们还将在体内共同刺激自主神经外周流出，以检查副交感神经紊乱在肥胖中的功能后果。激光捕获显微解剖副交感神经节神经元，然后进行qRT-PCR，将可以检查肥胖症的胆碱能标志基因。培养的心脏神经节神经元将有神经肽受体基因被敲除，以检测神经肽对乙酰胆碱合成和运输的调节。副交感神经功能减弱可导致心率控制失调，有可能导致心律失常，并间接导致儿茶酚胺中毒和工作负荷增加所致的心肌功能障碍。这些研究应该确定新的神经肽靶点来逆转肥胖者异常的副交感神经活动。此外，还将建立一种灵敏的高效液相色谱-质谱法同时测定神经化学物质。 与公共卫生相关：肥胖的一些心血管并发症可能是由投射到心脏的自主神经和控制心率之间的失衡引起的。这项研究旨在开发灵敏的分析方法来测量心脏神经释放的蛋白质。这些研究可以确定周围神经系统中的治疗部位，以逆转肥胖患者有害的心血管功能。

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. PUBLIC HEALTH RELEVANCE: Some cardiovascular complications of obesity may be caused by an imbalance between the autonomic nerves that project to the heart and control heart rate. This study aims to develop sensitive assays for measurement of proteins released by nerves in the heart. Therapeutic sites in the peripheral nervous system may be identified as a result of these studies for reversing detrimental cardiovascular function in obesity.