PHYSIOLOGY OF HYPOTHALAMIC NEUROHORMONES

下丘脑神经激素生理学：一种新的下丘脑 从绵羊下丘脑中分离得到38个残基的神经肽 基于腺苷环化酶刺激活性的大鼠组织 脑垂体细胞培养。测定了氨基酸序列，并测定了氨基酸序列。 人工合成的多肽与天然多肽在体内的活性相当。 腺苷环化酶刺激活性(ACSA)。缩写的 随后分离出具有27个残基的形式，并发现其为AS 活性为38个残基的多肽。这些多肽被命名为PACAP38 (38个残基的垂体腺苷酸环化酶激活多肽)和 PACAP27。这两种多肽都含有酰胺化 C-末端。尽管这些多肽是根据它们的ACSA分离出来的 在脑垂体细胞中，它们的生理作用尚不清楚。 因此，我们建议调查它们在 用合成的PACAPs制剂实现脑垂体细胞功能。这个 这项研究的直接目标是确定脑下垂体靶细胞 用组织化学和免疫组织化学方法检测PACAP在大鼠体内的表达。 然后我们将检查PACAP是否符合生理学要求 促垂体激素。该要求包括：(I)存在 大脑皮质外层致密的免疫阳性神经纤维网络 正中隆起；(Ii)肽对脑下垂体的直接作用 细胞及其特异性高亲和力结合部位的存在 (Iii)垂体门静脉血中PACAP浓度升高 在外周血液中；(4)澄清 PACAP在垂体细胞中的作用。如果PACAP是一种生理性的 脑下垂体的调节器，负反馈或正反馈 垂体和PACAP神经元之间可能相互作用的机制 下丘脑。此问题将使用以下工具进行调查 免疫组织化学、放射免疫法测定多肽和PACAP mRNA 在各种实验条件下的下丘脑。这个 PACAP的生理作用也将由 内源性PACAP作用的非中和化。

PHYSIOLOGY OF HYPOTHALAMIC NEUROHORMONES: A novel hypothalamic neuropeptide with 38 residues was isolated from ovine hypothalamic tissues based on its activity of adenylate cyclase stimulation in rat pituitary cell culutres. The amino acid sequence was determined and the synthetic peptide was found to be as active as the native peptide in terms of adenylate cyclase stimulating activity (ACSA). The shortened form with 27 residues was subsequently isolated and found to be as active as the 38 residue peptide. These peptides were named PACAP38 (Pituiary Adenylate Cyclase Activating Polypeptide with 38 residues) and PACAP27, repectively. Both of these peptides possessed amidated C-terminus. Although these peptides were isolated based on their ACSA in the pituitary cells, their physiological role remains unknown. Therefore, we propose to investigate their regulatory role in the pituitary cell function using synthetic preparations of PACAPs. The immediate goal of the study is to determine the pituitary target cells for PACAP using histochemical and immunohistochemical method in rats. Then we will examine if PACAP meets the requirement for a physiological hypophysiotropic hormone. The requirement includes (i) presence of dense net-work of immunopositive nerve fibers in the external layer of the median eminence; (ii) direct action of the peptide on the pituitary cells and presence of specific high affinity binding site in these cells (iii) greater concentration of PACAP in the hypophysial portal blood than in the peripheral blood; (iv) clarification of the end point of the action of PACAP in the pituitary cells. If PACAP is a physiological regulator of the pituitary gland, a negative or positive feed-back mechanism may interplay between the pituitary and PACAP neurons in the hypothalamus. This problem will be investigated using immunohistochemistry, RIA for determination of peptide, and PACAP mRNA in the hypothalamus under various experimental conditions. The physiological actions of PACAP will also be examined by the immnunoneutralization of the action of endogenous PACAP.