MOLECULAR MECHANISM OF ADENYLYL CYCLASE SUPERACTIVATION

超出所提供的空间。通过5类阿片受体起作用的镇痛药具有低成瘾性，但与经典阿片类药物相似，在长期治疗后表现出耐受性。慢性阿片受体刺激导致腺苷酸环化酶（AC）活性代偿性增加，称为AC超激活。我们已经证明，在人8阿片受体（hDOPJCHO）转染的CHO细胞中，AC同工酶（AC VI）在慢性5阿片受体激动剂（SNC 80）处理下被磷酸化。我们假设AC VI的磷酸化参与了腺苷酸环化酶的超激活，而这种超激活参与了对慢性阿片受体激动剂的耐受性。在初步实验中，我们发现o__transducin，一个假定的G蛋白133的清除者，-亚基，减弱慢性SNC 80介导的AC VI磷酸化和AC超激活。在这个提议中，我们将使用其他独立的方法来研究G蛋白133 -亚单位在细胞对急性和慢性SNC 80治疗反应中的作用。通过这些方法抑制AC超激活和AC VI磷酸化将证实G蛋白133 -亚单位在慢性SNC 80介导的反应中的作用。随后，我们将证明在慢性SNC 80治疗后释放的游离133，-亚单位可调节hDOR/CHO细胞中第二信使调节蛋白激酶和Raf-1蛋白激酶的活性。最后，我们将证明，hDOR/CHO细胞中负责AC VI磷酸化的蛋白激酶的耗竭也会减弱慢性阿片类激动剂介导的AC超激活。更好地了解人类阿片受体耐受药物的分子机制将有助于开发副作用更小的长效镇痛药。网站性能 ======================================== 节结束 ===========================================

EXCEED THE SPACE PROVIDED. Analgesics that act through the 5 opioid receptor have low addictive potential but similarly to classical opiates, display tolerance after long-term treatment. Chronic opioid receptor stimulation leads to a compensatory increase in adenylyl cyclase (AC) activity, called AC superactivation. We have demonstrated that an AC isoenzyme (AC VI) is phosphorylated upon chronic 5opioid agonist (SNC 80) treatment in CHO cells transfected with the human 8 opioid receptor (hDOPJCHO). We hypothesize that phosphorylation of AC VI is involved in adenylyl cyclase superactivation, and that superactivation is involved in tolerance to chronic 8 opioid agonists. In preliminary experiments we found that o_-transducin, a putative scavenger of G protein 133,- subunits, attenuated both chronic SNC 80 mediated phosphorylation of AC VI and AC superactivation. In this proposal we will use other, independent methods, to study the involvement of G protein 133,-subunitsin cellular responses to acute- and chronic SNC 80 treatment. Attenuation of AC superactivation and AC VI phosphorylation by these methods will confirm the role of G protein 133,-subunitsin chronic SNC 80-mediated respolises. Subsequently we will show that free 133,-subunitsr,eleased upon chronic SNC 80 treatment, regulate the activity of second messenger regulated protein kinases and Raf-1 protein kinase in hDOR/CHO cells. Finally, we will demonstrate that depletion of the protein kinase responsible for phosphorylation of AC VI in hDOR/CHO cells also attenuates chronic 8 opioid agonist mediated AC superactivation. Better understanding of the molecular mechanisms of drug tolerance at the human 5 opioid receptor should aid in the development of longer acting analgesics with fewer side effects. PERFORMANCE SITE ========================================Section End===========================================