ONTOGENY OF BETA-ENDORPHIN IN THE MEDULLA OBLONGATA

有证据表明，婴儿猝死综合症是一种 由于中枢呼吸中枢功能障碍， 神经系统 也有证据表明， 给予阿片肽可对脑缺血/再灌注产生降压作用。 延髓呼吸中枢 因为延髓是 几组不同的神经元的位置， 阿片样物质前体阿片样物质黑皮质素原、脑啡肽原和 强啡肽，这些内源性阿片样物质 肽系统可以调节延髓呼吸中枢。 动物模型的研究将有助于这一领域的研究 系统. 该提案的重点是前阿黑皮素系统中， 延髓的发育过程中。 的目标 这些项目是为了确定是否有发展 蛋白水解加工程度的变化， 黑皮质素和β-内啡肽的N-乙酰化程度 在胎儿和新生儿发育后期。 该项目将分两个阶段进行。 第一系列 实验将涉及稳态分析的形式， 前阿黑皮素相关的终产物。 组织 在胎仔第16天、第18天和新生儿第1、7、14和21天采集 将通过凝胶过滤分离，并通过 一系列特异性β-内啡肽，α-内啡肽， MSH和ACTH（1-39）。 β-乙酰化的程度 内啡肽和α-MSH将通过离子交换测定 分别通过色谱法和反相HPLC法进行分析。 第二个系列的实验将试图研究亲- 胚胎延髓神经元的阿黑皮素生物合成途径 在文化中。 分散的神经元将被脉冲氚化 酪氨酸和新合成的肽将被分离， 免疫亲和层析和通过SDS PAGE分析。 这些项目将提供深入了解发展 髓质中出现阿黑皮素原系统 长方形的 这些信息将有助于设计 实验测试内源性的潜在参与 β-内啡肽抑制延髓呼吸 复杂.

There is evidence that Sudden Infant Death Syndrome occurs as a result of a dysfunction of the respiratory centers in the central nervous system. There is also evidence that exogenous administration of opioid peptides can exert depressor action on the medullary respiratory centers. Since the medulla oblongata is the site of several distinct sets of neurons which synthesize the opioid precursors pro-opio-melanocortin, pro-enkephalin and pro- dynorphin, the possibility exists that these endogenous opioid peptide systems may modulate the medullary respiratory centers. Research in this area would be aided by studies on animal model systems. This proposal focuses on the pro-opiomelanocortin system in the medulla oblongata of the rat during ontogeny. The objectives of these projects are to determine whether there are developmental changes in the degree of proteolytic processing of pro-opio- melanocortin and the degree of N-acetylation of beta-endorphin during late fetal and neonatal development. The project will be approached in two phases. The first series of experiments will involve a steady state analysis of the forms of pro-opiomelanocortin-related end products in the medulla. Tissue collected at fetal day 16, day 18 and neonatal day 1, 7, 14, and 21 will be separately fractionated by gel filtration and analyzed by series of radioimmunoassays specific for beta-endorphin, alpha- MSH and ACTH(1-39). The degree of N-acetylation of beta- endorphin and alpha-MSH will be determined by ion exchange chromatography and reverse phase HPLC, respectively. The second series of experiments will attempt to study the pro- opiomelanocortin biosynthetic pathway in medullary fetal neurons in culture. Dispersed neurons will be pulsed with tritiated tyrosine and the newly synthesized peptides will be isolated by immunoaffinity chromatography and analyzed by SDS PAGE. These projects will provide insights into the developmental appearance of the pro-opiomelanocortin system in the medulla oblongata. This information will be useful for designing experiments to test the potential involvement of endogenous beta-endorphin in the depression of the medullary respiratory complex.