Investigation On The Behavior And Related Neuro-Electrochemistry Of Potential Medications For The Treatment Of Substance Use Disorders.

多巴胺(DA)转运体(DAT)是可卡因等滥用精神刺激剂的主要药理靶点，也是莫达非尼(MOD)等处方药的主要药理靶点，在临床或临床前研究中，莫达非尼几乎没有显示出滥用的倾向。最近，我们探索了MOD的神经化学和行为行为，以更好地描述其非典型的精神刺激特征。我们发现MOD刺激伏核外壳(NAS)和核心(NAC)DA水平的效力和效果低于可卡因，但与滥用的精神刺激剂不同，伏隔亚区之间的差异没有统计学意义。在药物辨别研究中，根据其DA效应，MOD在较低剂量和比预期更早的起效时间内显示出类似可卡因的主观效应。这些结果表明，非DA依赖的作用可能在其独特的药理学特征中发挥作用。为了发现这些MOD作用的潜在非多巴胺能机制，我们将其行为和神经化学效应与哌醋甲酯进行了比较。缝隙连接抑制剂Carbenoxolone可拮抗MOD，但不能增强自身给药的可卡因。我们的结果表明，MOD与可卡因和哌甲酸甲酯具有相同的机制，但具有独特的药理特征，包括促进电紧张性偶联和较低的滥用倾向，这可能被用于未来治疗可卡因使用障碍的药物设计。 尽管MOD可能被证明是一种对特定上瘾人群(例如，大量吸食强效可卡因的人，或者没有酒精滥用共病的可卡因和甲基苯丙胺成瘾者)有用的治疗方法，但更广泛有效的药物治疗精神刺激剂使用障碍仍然是一个未得到满足的医疗需求。为此，几个新合成的MOD类似物，例如JJC8-091和JJC8-088，已经在我们的临床前模型中作为治疗甲基苯丙胺和可卡因使用障碍的潜在药物进行了测试。 对JJC8-091和JJC8-088进行单独和与可卡因联合评估，以阐明神经化学与它们不同的行为特征的相关性。尽管有显著的结构相似性，JJC8-088更像可卡因，比JJC8-091更有效和更有效地增加NAS中的细胞外DA浓度。相比之下，JJC8-091不是自我给药，在阻止可卡因诱导的恢复药物寻找方面是有效的。电生理实验证实，JJC8-091比JJC8-088更有效地抑制可卡因诱导的DA神经传递增强。此外，当光刺激DAT-cre小鼠的VTA DA神经元时，JJC8-088使刺激-反应曲线显著左移，类似于可卡因，而JJC8-091使曲线下移，这表明DA介导的大脑奖励减弱。计算模型预测，虽然JJC8-088偏爱或稳定DAT的外向构象，如可卡因，但JJC8-091稳定DAT朝着更封闭的构象。 在最近的一篇文章中，我们表明可卡因和可卡因类典型精神刺激剂引起的DA动力学变化不同于非典型DAT阻滞剂通过伏安法测量的变化。当联合给药时，典型的DUI增强了可卡因对诱发的DA释放的刺激作用，而非典型的DUI则使它们变得迟钝。CaMKII是一种与DAT相互作用并调节突触蛋白磷酸化和DA囊泡储备池动员的酶，用CaMKII抑制剂预处理可钝化可卡因对诱发的DA释放的影响，提示CaMKII在调节可卡因对诱发的DA释放的影响而不影响可卡因抑制DA再摄取的作用。这种效应与可卡因稳定的特定DAT构象有关。此外，非典型的酒后驾驶，喜欢不同的DAT构象，钝化可卡因的神经化学和行为影响，表明它们作为治疗精神刺激剂使用障碍的药物的潜力的独特机制。 我们还扩大了我们的研究，以调查性别/性别在典型和非典型DAT阻滞剂的神经化学效应中的作用。我们发现可卡因减缓了雄性和雌性小鼠对DA的清除，但对雌性小鼠诱发的NAS DA产生了更强劲的增加。R-莫达非尼使诱发的NAS-DA轻度增加，并减缓了两性对DA的清除。莫达非尼类似物JJC8-088是一种典型的DAT抑制剂，可使雌性和雄性小鼠诱发的NAS-DA增加。最后，一种非典型的DAT抑制剂JJC8-091对诱发的NAS-DA产生有限的增加，并减缓了两性的DA清除。在这项工作中，我们开始梳理出性别差异如何改变DAT靶向的效果，并强调这如何有助于将研究重点放在心理刺激剂使用障碍的有效治疗选择上。 总而言之，这些数据揭示了DAT的潜在分子机制，该机制可用于合理优化治疗精神刺激剂使用障碍的先导。

The dopamine (DA) transporter (DAT) is the main pharmacologic target of abused psychostimulants like cocaine but also of prescribed medications like modafinil (MOD), which has shown little, if any, propensity for abuse in clinical or preclinical studies. Recently, we have explored the neurochemical and behavioral actions of MOD to better characterize its atypical psychostimulant profile. We found that MOD had a lower potency and efficacy than cocaine in stimulating nucleus accumbens shell (NAS) and core (NAC) DA levels, but, at variance with abused psychostimulants there were no statistically significant regional differences between accumbens subregions. In drug-discrimination studies MOD showed cocaine-like subjective effects at lower doses and earlier onset times than expected based on its DA effects. Those results suggest that non-DA-dependent actions may be playing a role in its unique pharmacological profile. In order to discover a potential non-dopaminergic mechanism for these MOD actions, we compared its behavioral and neurochemical effects with those of methylphenidate. Carbenoxolone, a gap junction inhibitor, antagonized MOD, but not methylphenidate potentiation of cocaine self-administration. Our results indicate that MOD shares mechanisms with cocaine and methylphenidate but has a unique pharmacological profile that includes facilitation of electrotonic coupling and lower abuse liability, which may be exploited in future therapeutic drug design for cocaine use disorder. Though MOD might prove useful as a treatment for specific addicted populations (e.g. heavy crack-cocaine users, or cocaine and methamphetamine addicts without alcohol abuse comorbidity), broader effective medications for psychostimulant use disorders are still an unmet medical need. To this end, several newly synthesized analogs of MOD, for example JJC8-091 and JJC8-088, have been tested in our preclinical models as potential medications for methamphetamine (METH) and cocaine use disorder. JJC8-091 and JJC8-088, were assessed alone and in combination with cocaine to elucidate neurochemical correlates to their divergent behavioral profiles. Despite sharing significant structural similarity, JJC8-088 was more cocaine-like, increasing extracellular DA concentrations in the NAS efficaciously and more potently than JJC8-091. In contrast, JJC8-091 was not self-administered and was effective in blocking cocaine-induced reinstatement to drug seeking. Electrophysiology experiments confirmed that JJC8-091 was more effective than JJC8-088 at inhibiting cocaine-mediated enhancement of DA neurotransmission. Further, when VTA DA neurons in DAT-cre mice were optically stimulated, JJC8-088 produced a significant leftward shift in the stimulation-response curve, similar to cocaine, while JJC8-091 shifted the curve downward, suggesting attenuation of DA-mediated brain reward. Computational models predicted that while JJC8-088 prefers or stabilizes an outward facing conformation of DAT, like cocaine, JJC8-091 stabilizes DAT towards a more occluded conformation. In a recent publication we show that cocaine and cocaine-like typical psychostimulants elicit changes in DA dynamics distinct from those elicited by atypical DAT blockers, as measured via voltammetry procedures. When given in combination, typical DUIs enhance the stimulatory effects of cocaine on evoked DA release while atypical DUIs blunt them. Pretreatments with an inhibitor of CaMKII, a kinase that interacts with DAT and that regulates synapsin phosphorylation and mobilization of reserve pools of DA vesicles, blunted the effects of cocaine on evoked DA release, suggesting a role for CaMKII in modulating the effects of cocaine on evoked DA release without affecting cocaine inhibition of DA reuptake. This effect is related to a specific DAT conformation stabilized by cocaine. Moreover, atypical DUIs, which prefer a distinct DAT conformation, blunt cocaine neurochemical and behavioral effects, indicating a unique mechanism underlying their potential as medications for treating psychostimulant use disorder. We have also extended our studies to investigate the role of sex/gender in the neurochemical effects of typical and atypical DAT blockers. We found that cocaine slowed DA clearance in both male and female mice but produced more robust increases in evoked NAS DA in female mice. R-modafinil produced mild increases in evoked NAS DA and slowed DA clearance across the sexes. The modafinil analog, JJC8-088, a typical DAT inhibitor, produced increases in evoked NAS DA in female and male mice. Finally, JJC8-091, an atypical DAT inhibitor, produced limited increases in evoked NAS DA and slowed DA clearance in both sexes. In this work we begin to tease out how sex differences may alter the effects of DAT targeting and highlight how this may help focus research toward effective treatment options for psychostimulant use disorder. Collectively, these data reveal the underlying molecular mechanism at DAT that may be leveraged to rationally optimize leads for the treatment of psychostimulant use disorder.