Activity of Preganglionic Neurons in Vitro

体外节前神经元的活性

• 批准号: 7352713
• 负责人: Nae J Dun
• 金额: $ 33.86万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-04-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7352713
• 关键词: 4-Aminopyridine; Abbreviations; Acute; Address; Adrenergic Agents; Adult; Affect; Amphetamines; Antibodies; Area; Arrhythmia; Biological; Biological Assay; Blood Circulation; Blood Pressure; CARTPT gene; Cardiovascular Abnormalities; Cardiovascular Diseases; Cell Nucleus; Cells; Chemical Stimulation; Chemicals; Choline O-Acetyltransferase; Chromosome Pairing; Chronic; Clinical; Closure; Cocaine; Cocaine Users; Complement component C1s; Corpus striatum structure; Dose; Epidemiologic Studies; Excitatory Postsynaptic Potentials; Fiber; Frequencies; Glass; Glutamates; Goals; Heart Rate; Immune Sera; Immunohistochemistry; In Situ; In Vitro; Infarction; Injection of therapeutic agent; Intrathecal Injections; Ischemia; Laboratories; Location; Membrane; Messenger RNA; Minor; Neurons; Neurotransmitters; Numbers; Oryctolagus cuniculus; Peptides; Peripheral; Pertussis Toxin; Phenylethanolamine N-Methyltransferase; Phosphate Buffer; Physiologic pulse; Physiological; Play; Process; Pulse taking; Rattus; Reverse Transcriptase Polymerase Chain Reaction; Risk; Role; Route; Saline; Serum; Signal Transduction Pathway; Site; Slice; Spinal Cord; Spinal Cord Column; Stroke; Sympathetic Nervous System; Synapses; Synaptic Transmission; Tea; Techniques; Tetraethylammonium; Tetrodotoxin; Therapeutic Agents; Transcriptional Activation; Tyrosine 3-Monooxygenase; Up-Regulation; Urethane; Vascular Diseases; Week; adrenergic; day; design; dorsal motor nucleus; immunoreactivity; in vivo; middle age; novel therapeutics; pituitary adenylate cyclase activating polypeptide; postsynaptic; presynaptic; receptor; research study; response

DESCRIPTION (provided by applicant): Epidemiological studies indicate a higher risk of myocardiac infarction, arrhythmia, stroke and ischemia in young and middle-aged adults who are "occasional" or "regular" cocaine users. Cocaine- and amphetamine-regulated transcript (CART) peptide is a recently identified peptide, the mRNA of which is up-regulated in certain central neurons following acute administration of cocaine or amphetamine. Subsequent studies including those from our laboratory show that CART peptide is expressed in a wide variety of central and peripheral neurons including the sympathetic preganglionic neurons (SPNs), which in turn receive CART-immunoreactive fibers possibly arising from neurons in the medullary C1 area. The central hypothesis is that CART peptide is excitatory to SPNs and that it is up-regulated by cocaine, resulting in an exaggerated sympathetic response in cocaine users. The goal of this project is to characterize in the rat the biological action of CART at the synapse of SPNs, with particular reference to circulation. First, immunohistochemical and tract-tracing studies will determine the location of CART neurons in the medulla or supramedullary nuclei that project to the SPNs. Second, microprobes coated with CART antiserum will be inserted into the intermediolateral cell column (IML) to assay the release of CART-immunoreactive substances from isolated spinal cords in situ or anesthetized rats in vivo. Third, RT-PCR will be used to establish whether or not CART mRNA is up-regulated in the medulla/spinal cord after acute and chronic injection of cocaine (10-20 mg/kg). Fourth, whole-cell patch recordings will be made from single SPNs in the transverse spinal cord slice and the effects of CART peptide on the electrical activity and synaptic transmission of these neurons will be studied. The mechanism and signal transduction pathways underlying the CART action will be investigated. Lastly, the physiological role of CART peptide, which will be administered by intrathecal route on blood pressure and heart rate will be assessed in urethane-anesthetized rats. A number of studies suggest that the sympathetic nervous system plays a major role in cocaine-induced cardiovascular abnormality. To be able to identify the neurotransmitter(s) and the circuitry that respond to cocaine would be a major step toward a better understanding of the intrinsic mechanisms that underlie cocaine-induced vascular disorders. More importantly, identification of putative transmitters involved in these processes would permit a rational approach to the design of novel therapeutics agents for the management of cocaine-induced cardiovascular disorder.

描述（由申请人提供）：流行病学研究表明，“偶尔”或“经常”使用可卡因的青壮年发生心肌梗塞、心律失常、中风和缺血的风险较高。可卡因和安非他明调节转录 (CART) 肽是最近发现的一种肽，在急性施用可卡因或安非他明后，其 mRNA 在某些中枢神经元中上调。随后的研究（包括我们实验室的研究）表明，CART 肽在多种中枢和外周神经元中表达，包括交感神经节前神经元 (SPN)，这些神经元反过来接收可能来自髓质 C1 区域神经元的 CART 免疫反应纤维。核心假设是 CART 肽对 SPN 具有兴奋性，并且可卡因会上调它，导致可卡因使用者产生过度的交感神经反应。该项目的目标是在大鼠中表征 CART 对 SPN 突触的生物作用，特别是循环方面。首先，免疫组织化学和纤维束追踪研究将确定投射到 SPN 的髓质或髓上核中 CART 神经元的位置。其次，将涂有CART抗血清的微探针插入中间外侧细胞柱（IML）中，以原位测定离体脊髓或体内麻醉大鼠释放的CART免疫反应物质。第三，RT-PCR将用于确定急性和慢性注射可卡因（10-20毫克/千克）后髓质/脊髓中的CART mRNA是否上调。第四，将从横向脊髓切片中的单个 SPN 进行全细胞贴片记录，并研究 CART 肽对这些神经元的电活动和突触传递的影响。将研究 CART 作用的机制和信号转导途径。最后，将在聚氨酯麻醉的大鼠中评估通过鞘内途径施用的 CART 肽对血压和心率的生理作用。许多研究表明，交感神经系统在可卡因引起的心血管异常中发挥着重要作用。能够识别对可卡因做出反应的神经递质和电路将是朝着更好地理解可卡因引起的血管疾病的内在机制迈出的重要一步。更重要的是，识别参与这些过程的推定递质将允许采用合理的方法设计用于治疗可卡因诱发的心血管疾病的新型治疗剂。