MORTPHINE-6 GLUCURONIDE--DEVELOPMENT OF BREATHING CONTRO

本研究的总体目标是检查新生豚鼠脑干中μ阿片受体的发育，以更好地了解子宫内长期吗啡暴露的呼吸效应以及吗啡的活性代谢产物吗啡-6-β-D-葡萄糖醛酸苷（M6 G）在呼吸抑制中的作用。 关于μ阿片受体研究的这一建议有三个主要方面，当结合起来时，使其独特。 它们是：1）位置，重点是脑干的呼吸核; 2）发育，重点是出生后第一周的新生动物; 3）治疗，重点是慢性间歇性与恒定速率的子宫内吗啡暴露。解剖学研究包括使用免疫组织化学、放射自显影、原位杂交和逆转录酶聚合酶链反应（RT-PCR）对μ阿片受体和受体mRNA进行定位和定量;药理学研究包括表征脑干膜和稳定转染的CHO细胞的结合特征;功能研究包括测定组织和细胞中阿片诱导的GTP γ S结合。 这些研究将提供有关mu受体在发育、吗啡诱导的呼吸抑制中的作用的新信息，重要的是，M6 G结合（与mu和潜在的非典型位点）在吗啡诱导的呼吸效应中的关系。假设是：1）在出生后的第一周内，脑干呼吸核中的D-Ala 2-MePhe 4-Gly-01 5-脑啡肽（DAMGO）结合和阿片样物质诱导的GTP γ S结合存在发育变化; 2）μ阿片样物质受体的发育变化受到子宫内吗啡暴露的影响;和3）[3 H]-DAMGO和[3 H]-M6 G结合与阿片样物质之间存在定量和定性差异，在出生后发育过程中和子宫内吗啡暴露后，在脑干中诱导GTP γ S结合。与呼吸核相关的阿片受体的变化对吗啡和M6 G对呼吸的影响有影响。 本研究对于因母体药物滥用、妊娠前阿片类药物滥用者维持治疗或疼痛治疗而在子宫内暴露于海洛因或其他阿片类药物的胎儿和新生儿具有重要意义。

The overall goal of this research is to examine the development of mu opioid receptors in the brainstem of the neonatal guinea pig in order to better understand the respiratory effects of chronic in utero morphine exposure and the role of morphine's active metabolite, morphine-6-beta-D-glucuronide (M6G), in respiratory depression. There are three main aspects to this proposal on the study of the mu opioid receptor that, when combined, make it unique. They are: 1) location, with the emphasis on the respiratory nuclei of the brainstem; 2) development, with the emphasis on the neonatal animal during the first week after birth; and 3) treatment, with the emphasis on chronic intermittent versus a constant rate of in utero morphine exposure. The anatomical studies include the localization and quantitation of mu opioid receptors and receptor mRNA using immunohistochemistry, autoradiography, in situ hybridization and reverse transcriptase polymerase chain reaction (RT-PCR); the pharmacological studies include characterization of binding profiles of brainstem membranes and stably transfected CHO cells; and the functional studies include the determination of opioid-induced GTPgammaS binding in tissue and cells. These studies will provide new information about the role of mu receptors in development, morphine-induced respiratory depression, and importantly, the relationship of M6G binding (to mu and to a potential atypical site) in morphine-induced respiratory effects. The hypotheses are: 1) that there are developmental changes in D- Ala2-MePhe4-Gly-ol5-enkephalin (DAMGO) binding and opioid-induced GTPgammaS binding in brainstem respiratory nuclei during the first week of life; 2) that developmental changes in the mu opioid receptor are affected by in utero morphine exposure; and 3) that there are quantitative and qualitative differences between [3H]-DAMGO and [3H]-M6G binding and opioid-induced GTPgammaS binding in the brainstem during postnatal development and following in utero morphine exposure. Changes in opioid receptors associated with respiratory nuclei have consequences for the effects of morphine and M6G on breathing. This study is of significance for the fetus and neonate who are exposed in utero to heroin or other opioids because of maternal drug abuse, maintenance therapy of pregnant former opioid abusers or pain therapy.