OPIOID AND G-PROTEIN REGULATION OF CALCIUM CURRENTS

阿片类药物和 G 蛋白对钙电流的调节

• 批准号: 2713058
• 负责人: HYLAN C MOISES
• 金额: $ 19.56万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-06-01 至 2002-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2713058
• 关键词: G protein; analgesics; calcium channel; calcium flux; calcium indicator; dielectric property; electrophysiology; endogenous opioid; exocytosis; hypothalamus; laboratory rat; nerve endings; neuroendocrine system; neurohypophysis; neurons; neuropharmacology; neurotransmitter transport; pain; receptor coupling; spinal ganglion; time resolved data; voltage /patch clamp; voltage gated channel

The long range goal of the proposed research is to understand the cellular and molecular mechanisms whereby opiates inhibit voltage-dependent calcium (Ca++) channels in mammalian neurons and to determine how this regulation relates to the ability of opiate analgesics to depress neurotransmitter release. This information is being sought, because it is through this presynaptic inhibitory action that opiates modulate the transmission of nociceptive information and exert their analgesic effects. The principal objectives of the research are to characterize the inhibitory coupling between opioid receptors and Ca++ channels in the nerve terminal and neuronal cell body with respect to the type and exocytotic function of the channels that are modulated and to determine the functional importance of alterations in voltage-dependent Ca++ signaling in mediating opioid inhibition of exocytotic release. The experiments will utilize whole-cell patch clamp techniques to record Ca++ currents in combination with monitoring of exocytosis using time-resolved measurements of membrane capacitance (Cm) in isolated peptidergic nerve endings and somata (currents only) of the hypothalamo-neurohypophysial system and in dissociated dorsal root ganglion (DRG) sensory neurons from adult rat. Using pharmacological blockers selective for specific types of Ca++ channels, together with specific voltage clamp protocols, we will determine whether the pattern of inhibitory coupling of opioid receptors to Ca++ channels expressed in supraoptic nucleus (SON) neurons parallels that for exocytotic channels in nerve endings that regulate vasopressin or oxytocin release. The relationship between opioid blockade of voltage- dependent Ca++ influx and inhibition of release will then be assessed by quantifying the effects of particular Ca++ channel antagonists and controlled alterations in [Ca++]i, measured with Fura-2, on the ability of kappa- or micro-opioid agonists to inhibit Ca++ currents and attenuate Cm responses in nerve ending and cell body preparations. In extending the analysis to functionally defined subsets of DRG neurons, we will determine the role of modulation in Ca++ influx and alterations in downstream components of the exocytotic process in mediating opioid inhibitory effects on the transmission of nociceptive signals. The proposed research, in contributing to a mechanistic understanding of opioid regulation of neurotransmission, should aid in the design of novel analgesic agents devoid of the tolerance or abuse liability characteristic of opiate drugs.

拟议研究的远距离目标是了解细胞 和分子机制，阿片类药物抑制电压依赖性钙 （CA ++）哺乳动物神经元中的通道，并确定该调节的方式 与阿片类镇痛药降低神经递质的能力有关 发布。 正在寻求此信息，因为它是通过此信息 鸦片的突触前抑制作用调节 伤害性信息并发挥其镇痛作用。 校长 研究的目标是表征抑制性耦合 在神经末端的阿片受体和CA ++通道之间 神经元细胞体相对于 调制并确定功能重要性的渠道 介导阿片类药物中电压依赖性Ca ++信号的改变 抑制胞吐释放。 实验将利用全细胞 贴片夹技术可记录CA ++电流 使用膜的时间分辨测量来监测胞吐作用 孤立肽吉尼神经末端的电容（cm）和somata （仅电流）下丘脑 - 神经型物理系统和 解散的背根神经节（DRG）从成年大鼠的感觉神经元。 使用药理学阻滞剂选择特定类型的CA ++ 通道，以及特定的电压夹协议，我们将 确定阿片受体抑制偶联的模式是否 在上核（SON）神经元中表达的Ca ++通道 对于调节加压素或 催产素释放。 阿片类电压阻断之间的关系 - 然后，依赖的CA ++涌入和释放的抑制作用将通过 量化特定的Ca ++通道拮抗剂和 以Fura-2测量的[Ca ++] I的受控改变， kappa-或微阿片类动力学家抑制Ca ++电流并衰减CM 神经结尾和细胞体制剂中的反应。 在扩展 分析DRG神经元功能定义的子集，我们将确定 调制在CA ++涌入和下游改变中的作用 介导阿片类药物抑制的胞吐过程的成分 对伤害性信号的传播的影响。 提议 研究，有助于对阿片类药物的机械理解 神经传递的调节，应有助于设计新颖 没有公差或虐待责任特征的镇痛药 阿片类药物。