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，从而提高麻醉品的药用价值。阿片类药物耐受性具有保护作用。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。到目前为止，对吗啡持续存在的适应通常分为两大类，一类是导致阿片受体介导的信号的实际丧失，另一类是通过其掩蔽导致这种活动的明显丧失。这些配方中几个值得注意的缺陷促使我们的实验室假设对慢性吗啡的适应性互补策略。与主流的耐受性模型相反，我们提出慢性吗啡诱导出现新的而不是丢失的信号后遗症。具体来说，我们证明了适应性促进了阿片受体偶联GPY刺激腺苷酸环化酶（AC）的出现，而不需要改变阿片受体G蛋白偶联。在目前的提案中，我们将在我们的配方中增加一个新的维度，即耐受性的结果部分来自持续的阿片受体GJG0信号传导的改变后果，包括与Gs的增强耦合。在此之前，这一直是有争议的，但现在基于我们最近的^-阿片受体（MOR） Gs关联的生化证明，这是令人信服的兴趣，慢性吗啡后显着增强。具体目标是：(1)确定参与耐受相关的MOR - Gs增强偶联的Gp亚型(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MOR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MOR - Gs功能偶联的影响；(5)确定信号平衡的靶向改变对先前定义的慢性吗啡神经化学适应的影响。这将证明，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耐受模型，该模型结合了信号分子中相互关联的趋同变化的动态马赛克，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.