OPIOID ACTIONS AND NEUROPEPTIDES

这是对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作用时间长 耐受依赖和禁欲过程。在本提案中， 基于本实验室的研究，将提出以下假设 证实：(A)Pro-Leu-Gly-NH2等神经肽抑制 作用于中枢神经系统的吗啡耐受依赖 中枢神经系统(CNS)、(B)多巴胺(DA)和特定区域的多种阿片受体 中枢神经系统与吗啡耐受、依赖和戒断有关 过程和(C)Pro-Leu-Gly-NH2(MIF)和环状(Leu-Gly)等肽 (CLG)通过以下方式抑制吗啡耐受依赖和戒断过程 影响多巴胺和阿片受体。研究将在小鼠和 以确定这是一种普遍现象还是与物种有关。 这些动物将通过以下方式对吗啡产生耐受性和依赖性 皮下植入吗啡微丸。容忍度 将通过测量反应进行评估(例如，止痛和 体温过低)对吗啡和安慰剂颗粒中不同剂量的吗啡 植入的啮齿动物。身体依赖程度将通过以下方式评估 确定体温过低、千篇一律的跳跃等症状的强度 在戒断吗啡的过程中体重减轻。多肽的作用 关于对吗啡的耐受和依赖的发展以及对 吗啡戒断症状将被确定。DA的约束性 受体配体~3H-SCH 23390和~H-多潘立酮(D_1和D_2受体， 分别)和阿片受体配体，~3H-DAMGO(MU)，~3H-DPDPE (Sigma)和~3H-U-69,593(K)到中枢神经系统区域(脊髓，杏仁核， 海马体、下丘脑、纹状体、脑桥和延髓、中脑和 大脑皮层)将被确定。初步研究表明，在 耐受依赖和戒断过程DA和阿片受体是 在中枢神经系统区域受到不同影响，因此将进行研究 有特定的大脑区域。为了确定CNS是否在 DA和阿片受体是通过阿片机制介导的。 纳曲酮对此类变化的影响将予以确定。一旦DA的特异性 而阿片受体的变化是确立的，那么第二个参与 信使系统(腺苷环化酶和磷酸肌醇)将 下定决心。不同程度的耐受性对小鼠免疫功能的影响 在不同时间间隔内植入不同数量的微丸 对上述生化指标进行监测。多肽的作用 给予脑室注射吗啡耐受性-将依赖 决心建立中心或外围的行动机制。为了测试 多肽通过改变多巴胺和多巴胺抑制吗啡耐受的假说 阿片受体及其在吗啡诱导的特异性改变中的作用 将确定CNS的区域。这些研究可能不仅会导致 更好地了解阿片成瘾过程的机制，但 也有助于在阿片类药物管理中开发更安全的药物 上瘾和痛苦的戒断综合症。

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.