REGULATION OF PITUITARY OPIATE PEPTIDE SECRETION

垂体阿片肽分泌的调节

• 批准号: 3402216
• 负责人: LINDA C SALAND
• 金额: $ 9.63万
• 依托单位: UNIVERSITY OF NEW MEXICO
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-08-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3402216
• 关键词: bioassay; catecholamines; corticotropin releasing factor; dopamine; endorphins; high performance liquid chromatography; hormone regulation /control mechanism; immunocytochemistry; immunoperoxidase; innervation; laboratory rat; ligands; melanocyte stimulating hormone; neural plasticity; neuropeptide receptor; neuropeptides; neurotoxins; neurotransmitter biosynthesis; pituitary gland; proopiomelanocortin; radioimmunoassay; secretion; serotonin

The major goals are to examine the extent of plasticity in regulatory mechanisms for pituitary opiate peptide secretion, both in young rats, and in aging animals. The major hypothesis to be tested is that innervation to pro-opiomelanocortin (POMC) cells of the pituitary intermediate lobe retains the ability to regenerate and regulate peptide secretion after denervation in young individuals, and that during aging, there is modulation of secretion as both nerves and endocrine cells undergo potential degenerative alterations. Questions are: 1. How do POMC endocrine cells respond to denervation and to potential re-innervation over time? Young adult male rats will be treated with a catecholamine neurotoxin, 6-hydroxydopamine (6-OHDA_, which induces neurite degeneration in pituitary. Immunoreactive catecholamine and serotonin innervation will be studied in drug treated and control animals over periods of 8 days, 3 and 6-8 weeks after treatment, to determine the extent of denervation, and of potential re-innervation of endocrine cells. 2. Do POMC cells modify their receptor population to adapt to denervation and potential re- innervation? Pituitary tissue of 6-OHDA treated rats will be studied using autoradiographic techniques with specific radioligands which bind to dopamine-2 (D-2) and serotonin-2 (5-HT-2) receptors, for alterations in receptor patterns which may occur with denervation and re-innervation. 3. How do POMC cells respond to specific regulatory molecules after denervation, and during potential re-innervation? Pituitaries of 6-OHDA treated animals will be incubated in vitro to examine direct effects of inhibitory or stimulatory molecules on peptides secretion. Peptides will be measured by radioimmunoassay (RIA) and tissues studied by immunocytochemical and electron microscopic (EM) techniques. 4. What changes occur in POMC secretory cells and their innervation during normal aging of individual animals? Pituitaries of aging rats (6, 12 and 18 months) will be examined for potential alterations in innervation patterns as well as for modulation of peptide secretion, using immunocytochemistry and RIA for tissue or blood samples. EM techniques will be used to correlate cytology of aging pituitaries with alteration in immunoreactive peptides. To determine if D-2 and 5-HT-2 receptors are altered with age, autoradiographic patterns of ligand binding will be examined. 5. Do aging POMC cells retain the ability to respond to regulatory molecules which inhibit or stimulate secretion? Pituitaries from aging rats will be studied in vitro using neurotransmitters and peptides which have been found to modulate opiate peptide release in young animals. Opiate peptides have significant effects on regulation of pain and on homeostatic mechanisms related to stress. Investigations of plasticity of regulatory mechanisms, in the forms of potential neurite regeneration and modulation of receptor patterns on POMC cells, both in young and aging animals, will be a basis for appropriate pharmacologic manipulation of opiate peptide secretion, in animal models, and in man.

主要目标是检查监管的可塑性程度 年轻大鼠垂体阿片肽分泌的机制，以及 在衰老的动物中。 要检验的主要假设是神经支配 垂体中叶阿片黑皮素原 (POMC) 细胞 保留再生和调节肽分泌的能力 年轻人的去神经支配，以及在衰老过程中， 神经和内分泌细胞经历分泌调节 潜在的退行性改变。 问题是： 1. POMC如何做 内分泌细胞对去神经支配和潜在的神经再支配做出反应 时间？ 年轻的成年雄性大鼠将接受儿茶酚胺治疗 神经毒素，6-羟基多巴胺（6-OHDA_，可诱导神经突变性 在垂体中。 免疫反应性儿茶酚胺和血清素神经支配将 在药物治疗和对照动物中进行为期 8 天的研究，3 治疗后 6-8 周，确定去神经支配的程度，以及 内分泌细胞的潜在重新神经支配。 2. POMC细胞会改变吗 他们的受体群体适应去神经支配和潜在的重新 神经支配？ 将使用 6-OHDA 处理的大鼠的垂体组织进行研究 使用特定放射性配体的放射自显影技术 多巴胺-2 (D-2) 和血清素-2 (5-HT-2) 受体，用于改变 去神经支配和重新神经支配时可能发生的受体模式。 3. POMC细胞如何对特定的调节分子做出反应 去神经支配，以及潜在的重新神经支配期间？ 6-OHDA 的垂体 接受治疗的动物将在体外培养，以检查直接影响 肽分泌的抑制或刺激分子。 肽会 通过放射免疫测定（RIA）进行测量，并通过以下方法研究组织 免疫细胞化学和电子显微镜（EM）技术。 4. 什么 POMC 分泌细胞及其神经支配在正常情况下发生变化 动物个体的衰老？ 衰老大鼠（6、12 和 18 岁）的垂体 月）将检查神经支配模式的潜在变化 以及使用免疫细胞化学调节肽分泌 以及用于组织或血液样本的 RIA。 EM 技术将用于 将衰老垂体的细胞学与免疫反应性的改变相关联 肽。 为了确定 D-2 和 5-HT-2 受体是否随着年龄的增长而改变， 将检查配体结合的放射自显影模式。 5.做老化 POMC 细胞保留了对调节分子作出反应的能力 抑制或刺激分泌？ 衰老大鼠的垂体将 使用已发现的神经递质和肽进行体外研究 调节幼年动物中阿片肽的释放。 阿片肽具有 对疼痛调节和稳态机制有显着影响 与压力有关。 调节机制可塑性的研究， 以潜在的神经突再生和受体调节的形式 年轻和老年动物 POMC 细胞的模式将成为基础 用于阿片肽分泌的适当药理学操作， 动物模型和人体。