THE ROLE OF RYANODINE RECEPTORS IN DRUG SEEKING

目前没有有效的药物治疗方案来预防可卡因和海洛因的复吸 寻找这是由于缺乏对潜在的适应不良细胞机制的理解 驱动这种行为。相当多的证据表明，前额叶皮层（PFC）的投射到 黑质核核心（NAcore）代表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锥体神经元的持续超兴奋性。的 超兴奋性与细胞内Ca 2+升高有关，而Ca 2+升高可能是由兰尼定功能障碍引起的 受体（RYR）。过量的Ca 2+抑制抑制性Kv 7离子通道，其用于限制神经元放电。 值得注意的是，这种药物诱导的细胞信号传导功能障碍即使在药物延长消退后也会持续存在- 强化行为因此，PFC神经元的一个亚群保持高度兴奋， 对药物相关线索过敏在海马神经元中，压力引起的过度刺激与 伴随RYR 2的磷酸化和氧化以及稳定亚基钙蛋白2（FKBP 12.6）的耗竭 从通道复合物中释放，导致细胞内Ca 2+通过RYR泄漏和认知功能障碍。一种新型 RYR靶向小分子Rycal（S107），稳定PKA的RYR 2闭合状态 过度磷酸化和氧化/亚硝基化通道，防止细胞内Ca 2+泄漏，并防止细胞内Ca 2+泄漏。 压力导致的认知缺陷我们的初步数据表明，S107治疗也减少了线索诱导的 老鼠体内的可卡因该项目的长期目标是了解细胞信号传导， RYRs调节复发行为的生理机制，希望找到更好的治疗方法。 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的病理性不稳定，2）引起RYR- 激活的PFC神经元内投射到延髓核核心（NAcore）的依赖性Ca 2+泄漏，以及3） RYR稳定剂S107的抗复发作用至少部分是由于其降低RYR的能力 Ca 2+“渗漏”。为了更好地理解PFC抑制中持久适应的细胞起源，我们建议 为了检查：Aim 1中RYR的氧化还原状态和RYR和FKBP 12.6两者中的一系列生物化学变化， 目标2中特定神经元亚群中的RYR变化，以及最后的翻译策略， 减少目标3中药物寻求的线索复发。总之，这些研究将扩大我们广泛的 初步研究结果表明，RYR氧化还原状态和候选成瘾治疗，S107调节 的复发样行为，驱动PFC中观察到的持久变化。我们将确定， 可卡因和海洛因对PFC RYR 2和/或FKBP 12.6的破坏是复吸所必需的， 支持治疗海洛因和可卡因的药物开发新靶点的临床前机制数据 成瘾

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.