Adenylyl Cyclase GBetaGamma Stimulation and Opioid Tolerance

描述（由申请人提供）：阿片类药物耐受性的研究继续受到信念的启发，即阐明与这种情况因果相关的适应性将促进药物治疗的发展，以改善其状况，从而提高麻醉剂的药用价值。阿片类药物耐受性是保护性的。它与广泛的神经化学变化有关，这些变化被认为是适应性的。迄今为止已经确定的对吗啡持续存在的适应通常分为两大类，导致阿片受体介导的信号传导的实际损失的适应和通过其掩蔽导致这种活性明显损失的适应。这些制剂中的几个值得注意的缺陷促使我们的实验室假设适应慢性吗啡的补充策略。与流行的耐受模型相反，我们提出慢性吗啡诱导出现新的，但不是丢失的信号后遗症。具体来说，我们证明了适应，促进阿片受体偶联的GPY刺激腺苷酸环化酶（AC）的出现，不需要改变阿片受体G蛋白偶联。在目前的提案中，我们将增加一个新的方面，我们的配方，耐受性的结果，部分，从改变的后果，继续阿片受体GJG 0信号传导，包括增强耦合到Gs。迄今为止，这一直是有争议的，但现在基于我们最近对β-阿片受体（莫尔）Gs相关性的生物化学证明而引起了极大的兴趣，该相关性在慢性吗啡后显著增强。具体的目的是（1）确定参与耐受相关的增强的莫尔Gs偶联的GP同种型（2）确定慢性吗啡降低GSa磷酸化的能力及其机制，从而增强其与莫尔的关联，（3）确定GSa磷酸化对其与AC相互作用的影响，（4）确定慢性吗啡对莫尔Gs功能偶联的影响和（5）确定信号平衡的靶向改变对先前定义的对慢性吗啡的神经化学适应的影响。这将确定公差适应不是硬连线的，而是取决于初始稳态条件。总的来说，拟议的研究将有助于建立一个模型的耐受性，包括一个动态的马赛克收敛相互关联的变化信号分子，试图重建功能平衡。

DESCRIPTION (provided by applicant): Research on opioid tolerance continues to be inspired by the conviction that elucidation of the adaptations causally associated with this condition will facilitate the development of pharmacotherapies for its amelioration and thus enhance the medicinal usefulness of narcotics. Opioid tolerance is protective. It has been associated with a wide spectrum of neurochemical changes believed to be adaptive. Adaptations to the persistent presence of morphine that have thus far been identified generally fall into two main categories, those that result in the actual loss of opioid receptor-mediated signaling and those that result in the apparent loss of this activity via its masking. Several noted deficiencies in these formulations prompted our laboratory to hypothesize complimentary strategies of adaptation to chronic morphine. In contrast to prevailing models of tolerance, we proposed that chronic morphine induces the emergence of new, but not lost, signaling sequelae. Specifically, we demonstrated adaptations that facilitated the emergence of opioid receptor- coupled GPY stimulation of adenylyl cyclase (AC) that did not require altered opioid receptor G protein coupling. In the current proposal, we will add a new dimension to our formulation that tolerance results, in part, from the altered consequences of continued opioid receptor GJG0 signaling to include enhanced coupling to Gs. This has heretofore been controversial but is now of compelling interest based on our recent biochemical demonstration of ^-opioid receptor (MOR) Gs association, which is markedly enhanced following chronic morphine. The specific objectives are to (1) Determine the Gp isoforms that participate in tolerance- associated enhanced MOR Gs coupling (2) Determine the ability of chronic morphine, and mechanisms thereof, to decrease phosphorylation of GSa, and thereby enhance its association with MOR, (3) Determine the influence of GSa phosphorylation on its interaction with AC, (4) Determine the influence of chronic morphine on MOR Gs functional coupling and (5) Determine the effect of targeted alteration of signaling equilibria on previously defined neurochemical adaptations to chronic morphine. This will establish that tolerance adaptations are not hard wired but depend on initial steady state conditions. Collectively, proposed studies will help establish a model of tolerance that incorporates a dynamic mosaic of convergent interrelated changes in signaling molecules in an attempt to reestablish functional equilibria.