OPIOID ACTIONS AND NEUROPEPTIDES

这是ADAMHA研究科学家发展奖（K02）的申请。 长期目标是开发具有口服活性的神经肽类似物， 抑制吗啡的酶稳定性和长期作用 耐受依赖和禁欲过程。 在本提案中， 根据该实验室的研究，将提出以下假设 验证：（a）神经肽如Pro-Leu-Gly-NH2和类似物抑制 作用于中枢神经系统的吗啡耐受-依赖 (CNS)、（B）多巴胺（DA）和特定区域的多种阿片受体 参与吗啡耐受-依赖和戒断 过程和（c）肽如Pro-Leu-Gly-NH2（MIF）和环（Leu-Gly） (CLG)抑制吗啡耐受-依赖和戒断过程， 影响多巴胺和阿片受体 研究将在小鼠中进行， 大鼠，以确定这是一种普遍现象还是种属依赖性。 通过以下方法使动物对吗啡产生耐受性和依赖性： 皮下植入吗啡丸。 的耐受程度 将通过测量反应（例如镇痛和 低温）对吗啡和安慰剂丸中不同剂量吗啡 植入的啮齿动物 身体依赖程度将通过以下方式进行评估： 确定症状的强度，如体温过低，刻板的跳跃， 以及吗啡戒断期间的体重减轻 肽的作用 对吗啡的耐受性和依赖性的发展， 将确定吗啡戒断的症状。 DA结合 受体配体3H-SCH 23390和3H-多潘立酮（D1和D2受体， 和阿片受体配体，3H-DAMGO（μ），3H-DPDPE （sigma）和3H-U-69，593（k）至CNS区域（脊髓，杏仁核， 海马、下丘脑、纹状体、脑桥和髓质、中脑和 大脑皮层）将被确定。 初步研究显示， 耐受依赖和戒断过程DA和阿片受体 在中枢神经系统区域受到不同的影响，因此将进行研究 特定的大脑区域。 为了确定中枢神经系统是否发生变化， DA和阿片受体通过阿片机制介导， 将对这些变化进行测定。 一旦DA的特异性 和阿片受体的变化，然后参与第二次 信使系统（腺苷酸环化酶和磷酸肌醇）将被 测定 诱导的不同程度的耐受性的影响 在不同的时间间隔内植入不同数量的弹丸， 将监测上述生化参数。 肽的作用 在吗啡耐受性依赖的脑室内给药， 决定建立中枢或外周作用机制。 测试 肽类通过修饰DA抑制吗啡耐受的假说， 阿片受体及其对吗啡诱导的特异性 将确定CNS的区域。 这些研究可能不仅会导致 更好地了解阿片类药物成瘾过程的机制， 也有助于开发更安全的药物来管理阿片类药物， 成瘾和痛苦的戒断综合征。

This is a request for an ADAMHA Research Scientist Development Award (K02). the long term goal is to develop neuropeptide analogs with oral activity, enzymatic stability and long duration of action in inhibiting morphine tolerance-dependence and abstinence processes. In the present proposal, based on the studies from this laboratory, the following hypotheses will be verified: (a) neuropeptides like Pro-Leu-Gly-NH2 and analogs inhibit morphine tolerance-dependence by acting on the central nervous system (CNS), (b) dopamine (DA) and multiple opiate receptors of specific regions of the CNS are involved in morphine tolerance-dependence and abstinence processes and (c) peptides like Pro-Leu-Gly-NH2 (MIF) and cyclo(Leu-Gly) (CLG) inhibit morphine tolerance-dependence and abstinence processes by affecting DA and opiate receptors. Studies will be carried out in mice and rats to establish if it is a general phenomena or is species dependent. The animals will be made tolerant to and dependent on morphine by subcutaneous implantation of morphine pellets. The degree of tolerance will be assessed by measuring the responses (e.g. analgesia and hypothermia) to varying doses of morphine in morphine and placebo pellet implanted rodents. the degree of physical dependence will be assessed by determining the intensity of symptoms like hypothermia, stereotyped jumping and weight loss during the withdrawal of morphine. The effect of peptides on the development of tolerance to and dependence on morphine and on the symptoms of morphine abstinence will be determined. the binding of DA receptor ligands 3H-SCH 23390 and 3H-domperidone (D1 and D2 receptors, respectively) and of opiate receptor ligands, 3H-DAMGO (mu), 3H-DPDPE (sigma) and 3H-U-69,593 (k) to CNS regions (spinal cord, amygdala, hippocampus, hypothalamus, corpus striatum, pons and medulla, midbrain and cerebral cortex) will be determined. Preliminary studies show that in tolerance-dependence and abstinence processes DA and opiate receptors are affected differentially in CNS regions, hence studies will be carried out with specific brain regions. In order to establish whether CNS changes in DA and opiate receptors are mediated via opiate mechanism the effect of naltrexone on such changes will be determined. Once the specificity of DA and opiate receptor changes is established, then the involvement of second messenger systems (adenylate cyclase and phosphoinositol) will be determined. the effect of different degrees of tolerance induced by implanting different number of pellets during different time intervals on the above biochemical parameters will be monitored. Effect of peptides given intracerebroventricularly on morphine tolerance-dependence will be determined to establish central or peripheral mechanism of action. To test the hypothesis that peptides inhibit morphine tolerance by modifying DA and opiate receptors, their effect on morphine induced changes in specific regions of the CNS will be determined. These studies may lead not only to better understanding of the mechanisms in opiate addiction processes but also to the development of safer drugs in the management of opioid addiction and distressing withdrawal syndrome.