THE ROLE OF RYANODINE RECEPTORS IN DRUG SEEKING

目前还没有有效的药物治疗选择来防止可卡因和海洛因复发。 寻找。这主要是由于缺乏对潜在的适应不良细胞机制的了解。 驱使着这种行为。大量证据表明，前额叶皮质(PFC)投射到 伏隔核核心(NAcore)是触发复发的主要共同途径。最近，我们 在大鼠中发现可卡因或海洛因SA诱导PFC锥体神经元持续的高兴奋性。这个 兴奋性亢进与兰尼定功能障碍引起的细胞内钙离子升高有关 受体(RYRs)。过量的钙离子抑制抑制的KV7离子通道，从而限制神经元的放电。 值得注意的是，这种由药物引起的细胞信号故障即使在药物长期停用后仍然存在- 强化的行为。因此，PFC神经元的一个亚群仍然高度兴奋，很可能 对与药物有关的线索过敏。在海马神经元中，应激过度刺激是相关的 与RYR2的磷酸化和氧化以及稳定亚单位钙稳定蛋白2(FKBP12.6)的缺失有关 从通道复合体，导致细胞内钙离子通过RYRs泄漏和认知功能障碍。一本小说 稳定PKA RYR2封闭态的RyR靶向小分子Rycal(S107) 过度磷酸化和氧化/亚硝化的通道，防止细胞内钙泄漏，防止 压力导致的认知缺陷。我们的初步数据表明，S107处理也减少了线索诱导的 在老鼠身上寻找可卡因。这个项目的长期目标是了解细胞信号和 RYRs调节复发行为以期找到更好的治疗方法的生理机制 治疗药物成瘾的策略。我们的中心假设是：(1)可卡因和海洛因- 通过氧化还原翻译后修饰产生RyR的病理不稳定，2)导致RyR- 激活的投射到伏核核心的PFC神经元(NAcore)内的依赖性钙泄漏，以及3) RyR稳定剂S107的抗复发作用至少部分归因于它降低RyR的能力 Ca2+“渗漏”。为了更好地理解PFC抑制中持久适应的细胞来源，我们提出 检查目标1中RyR的氧化还原状态以及RyR和FKBP12.6的一系列生化变化， Aim 2中特定神经元亚群中RyR的变化，最后是针对 在AIM 3中减少线索恢复药物寻找。总之，这些研究将扩大我们广泛的 初步发现RyR氧化还原状态和候选成瘾治疗S107与调控有关 推动在PFC中观察到的长期变化的复发类行为。我们将确定是否 可卡因和海洛因干扰PFC RYR2和/或FKBP12.6是复发所必需的，并将提供 临床前机械性数据支持治疗海洛因和可卡因的药物开发新靶点 上瘾。

There currently exist no effective pharmacological treatment options to prevent relapse to cocaine and heroin seeking. This is due to a principal lack of understanding of the underlying maladaptive cellular mechanisms driving this behavior. Considerable evidence suggests that the pre-frontal cortex (PFC) projection to the nucleus accumbens core (NAcore) represents a principle common pathway for triggering relapse. Recently, we found in rats that cocaine or heroin SA induces persistent hyper-excitability in PFC pyramidal neurons. The hyperexcitability is related to elevated intracellular Ca2+ that likely arises from malfunctioning ryanodine receptors (RYRs). Excess Ca2+ suppresses inhibitory Kv7 ion channels that serve to limit neuronal firing. Notably, this drug-induced malfunction in cell signaling persists even after extended extinction of the drug- reinforced behavior. As a result, a subpopulation of PFC neurons remains hyper-excitable and likely hypersensitive to drug-associated cues. In hippocampal neurons, excessive stimulation by stress is associated with phosphorylation and oxidation of RYR2 and depletion of the stabilizing subunit calstabin2 (FKBP12.6) from the channel complex, resulting in intracellular Ca2+ leak through RYRs and cognitive dysfunction. A novel RYR-targeted small molecule Rycal (S107) that stabilizes the RYR2 closed states of PKA hyperphosphorylated, and oxidized/nitrosylated channels, prevents intracellular Ca2+leak and prevented the stress-induced cognitive defects. Our preliminary data indicate that S107 treatment also reduces cue-induced cocaine seeking in rats. The long-term goal of this project is to understand the cellular signaling and physiological mechanisms by which RYRs regulate relapse behavior in hopes of identifying better therapeutic strategies for the treatment of drug addiction. Our central hypotheses are that: (1) cocaine- and heroin- produces pathological destabilization of RYR via redox post-translational modification, 2) causing RYR- dependent Ca2+ leak within activated PFC neurons projecting to the nucleus accumbens core (NAcore), and 3) that the anti-relapse effects of the RYR stabilizer S107 are due, at least in part, to its ability to reduce RYR Ca2+ “leak”. To better understand the cellular origin of the enduring adaptations in PFC inhibition, we propose to examine: the redox state of RYR and a battery of biochemical changes in both RYR and FKBP12.6 in Aim 1, RYR changes in specific subpopulations of neurons in Aim 2, and lastly translational strategies aimed at reducing cued reinstatement of drug seeking in Aim 3. Together, these studies will extend our extensive preliminary findings that link the RYR redox state and the candidate addiction therapeutic, S107 to regulation of relapse-like behaviors that drive the long-lasting changes observed in the PFC. We will determine if disruption of the PFC RYR2 and/or FKBP12.6 by cocaine and heroin is necessary for relapse and will provide mechanistic preclinical data in support of a novel target for drug development to treat heroin and cocaine addiction.