OPIATE AND ENDORPHIN EFFECTS ON CNS TISSUE CULTURES

阿片和内啡肽对中枢神经系统组织培养的影响

• 批准号: 3207080
• 负责人: STANLEY M CRAIN
• 金额: $ 19.16万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-07-01 至 1989-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3207080
• 关键词: actinomycin; action potentials; adenylate cyclase; autoradiography; cyclic AMP; cycloheximide; dorsal root; drug addiction antagonist; drug tolerance; electrophysiology; embryo /fetus tissue /cell culture; embryo /fetus toxicology; ganglions; mixed tissue /cell culture; morphine; naloxone; neuropharmacology; neurotrophic factors; nucleotide analog; opiate alkaloid; pregnancy; radiotracer; silver impregnation; tetrodotoxin; tissue /cell culture

Electrophysiologic analyses during chronic application of opioids to organotypic explants of fetal mouse spinal cord with attached dorsal root ganglia (DRGs) demonstrate that isolated mammalian CNS tissues can develop marked tolerance after several days' exposure in vitro. The marked decreases in opioid sensitivity of DRG-evoked dorsal-horn network responses observed during chronic opioid exposure of cord-DRG explants will be closely coordinated with biochemical assays to test the hypothesis that the physiologic expression of tolerance may be mediated by significant enhancement of adenylate cyclase activity and cyclic AMP levels. These studies will be correlated with analyses of the acute tolerance-like state produced by brief exposure of cord-DRG explants to forskolin or other agents that elicit a rise in intracellular cyclic AMP. In order to clarify other factors that may regulate opioid tolerance, correlative physiologic and biochemical analyses will be made after physicochemical alterations of the culture environment during chronic opioid exposure, e.g. addition of specific metabolic or pharmacologic blocking agents. Extracellular recordings of dorsal-horn responses during chronic exposure to opioids--or acute exposure to forskolin and cyclic AMP analogs--will be correlated with intracellular recordings from the DRG and cord neurons. These analyses will clarify pre-and post-synaptic alterations in dorsal-horn network functions that may occur in tolerant explants. Factors leading to the marked upregulation of opiate receptor levels that occurs in mature cord-DRG explants after chronic exposure to naloxone will be analyzed, using specific metabolic/pharmacologic blocking agents and autoradiography. Electrophysiologic analyses, binding assays and autoradiography will be coordinated to determine if developmental redistribution, disappearance, or functional inactivation of opiate receptors may account for the spinal cord-regulated decrease in the fraction of opioid-sensitive DRG neuron perikarya observed in DRG-cord vs. isolated DRG explants. Development of opioid dorsal-horn networks and their DRG inputs will also be studied during chronic exposure of embryonic tissues to opioid agonists or antagonists at early stages in vitro. The proposed studies should provide valuable insights into mechanisms of tolerance and plasticity in opioid systems of the CNS and problems in maternal narcotic addiction.

长期使用阿片类药物期间的电生理分析 附有背根的胎鼠脊髓器官型外植体 神经节（DRG）证明分离的哺乳动物中枢神经系统组织可以发育 体外暴露数天后显着耐受。 所标记的 DRG 诱发的背角网络反应的阿片类药物敏感性降低 在脐带 DRG 外植体的慢性阿片类药物暴露期间观察到的结果将 与生化测定密切配合，以检验以下假设： 耐受的生理表达可能是由显着介导的 增强腺苷酸环化酶活性和环AMP水平。 这些 研究将与急性耐受样状态的分析相关 通过将脐带 DRG 外植体短暂暴露于毛喉素或其他物质而产生 引起细胞内环磷酸腺苷升高的药物。 为了澄清 其他可能调节阿片类药物耐受性的因素，相关生理学 理化改变后进行生化分析 慢性阿片类药物暴露期间的培养环境，例如添加 特定的代谢或药理学阻断剂。 长期暴露期间背角反应的细胞外记录 阿片类药物 - 或急性暴露于毛喉素和环 AMP 类似物 - 将 与 DRG 和脊髓神经元的细胞内记录相关。 这些分析将阐明突触前和突触后的变化 背角网络功能可能发生在耐受性外植体中。 导致阿片受体水平显着上调的因素 长期暴露于纳洛酮后，成熟的脐带 DRG 外植体中会发生这种情况 使用特定的代谢/药理学阻断剂进行分析，并且 放射自显影。 电生理分析、结合测定和 将协调放射自显影以确定发育是否 阿片类药物的重新分布、消失或功能失活 受体可能是脊髓调节的减少的原因 在 DRG-cord 与 DRG-cord 中观察到的阿片类药物敏感性 DRG 神经元周核的分数 分离的 DRG 外植体。 阿片类药物背角网络的发展和 他们的 DRG 输入也将在胚胎长期暴露期间进行研究 在体外早期阶段组织对阿片类激动剂或拮抗剂的作用。 拟议的研究应该为机制提供有价值的见解 中枢神经系统阿片类药物系统的耐受性和可塑性及其问题 母亲吸毒成瘾。