中枢神经降压素可能诱导大鼠下丘脑室旁核前交感神经元中环氧化酶-1 的 S-亚硝基化。

Central bombesin possibly induces S-nitrosylation of cyclooxygenase-1 in pre-sympathetic neurons of rat hypothalamic paraventricular nucleus.

机构信息

Department of Pharmacology, Kochi University School of Medicine, Nankoku, Kochi 783-8505, Japan.

出版信息

Life Sci. 2014 Apr 1;100(2):85-96. doi: 10.1016/j.lfs.2014.01.079. Epub 2014 Feb 13.

DOI:10.1016/j.lfs.2014.01.079

PMID:24530741

Abstract

AIMS

Cyclooxygenase (COX) can be activated by nitric oxide-induced (NO-induced) conversion of cysteine thiol group of COX into S-nitrosothiol. We previously reported the involvement of brain COX/NO synthase (NOS) in centrally administered bombesin-, a stress-related neuropeptide, induced secretion of rat adrenal noradrenaline and adrenaline. To examine a possible involvement of the NO-induced modification of COX in bombesin-induced response, we investigated whether bombesin induces close proximity of COX-1 and neuronal NOS (nNOS) or S-nitroso-cysteine in pre-sympathetic spinally projecting neurons in the rat hypothalamic paraventricular nucleus (PVN), a regulatory center of adrenomedullary outflow.

MAIN METHODS

In twelve-week-old male Wistar rats, pre-sympathetic spinally projecting neurons in the PVN were labeled with a retrograde tracer Fluoro-Gold (FG). After intracerebroventricular administration of bombesin, we performed double immunohistochemical analysis for Fos and COX-1 or nNOS in FG-labeled PVN neurons. We also performed a fluorescent in situ proximity ligation assay (PLA) for visualizing of close proximity (<40 nm) of COX-1 with nNOS or S-nitroso-cysteine.

KEY FINDINGS

Bombesin significantly increased the number of Fos-immunoreactive cells in FG-labeled PVN neurons with COX-1 or nNOS immunoreactivity. 7-Nitroindazole, a selective nNOS inhibitor, abolished Fos-immunoreactivity induced by bombesin in COX-1-immunoreactive FG-labeled PVN neurons. Bombesin also induced PLA-positive signals indicating close proximity of COX-1/nNOS and COX-1/S-nitroso-cysteine in FG-labeled PVN neurons.

SIGNIFICANCE

Centrally administered bombesin possibly induces S-nitrosylation of COX-1 through close proximity of COX-1 and nNOS in pre-sympathetic spinally projecting PVN neurons, thereby activating COX-1 during the bombesin-induced activation of central adrenomedullary outflow in the rat.

摘要

目的

环氧化酶（COX）可被一氧化氮诱导（NO 诱导）的半胱氨酸巯基转换为 S-亚硝基硫醇而激活。我们之前报道了脑 COX/一氧化氮合酶（NOS）参与了中枢给予的神经肽脑肠肽诱导的大鼠肾上腺去甲肾上腺素和肾上腺素的分泌。为了研究 COX 的 NO 诱导修饰是否参与脑肠肽诱导的反应，我们研究了脑肠肽是否诱导 COX-1 和神经元型 NOS（nNOS）或 S-亚硝基半胱氨酸在大鼠下丘脑室旁核（PVN）中投射到脊髓的交感前神经元中的接近。PVN 是肾上腺髓质流出的调节中心。

主要方法

在 12 周龄雄性 Wistar 大鼠中，用逆行示踪剂 Fluoro-Gold（FG）标记 PVN 中的交感前脊髓投射神经元。脑室内给予脑肠肽后，我们对 FG 标记的 PVN 神经元中的 Fos 和 COX-1 或 nNOS 进行双重免疫组织化学分析。我们还进行了荧光原位邻近连接分析（PLA），以观察 COX-1 与 nNOS 或 S-亚硝基半胱氨酸的接近程度（<40nm）。

主要发现

脑肠肽显著增加了 FG 标记的 PVN 神经元中 COX-1 或 nNOS 免疫反应性的 Fos 免疫反应性细胞的数量。7-硝基吲唑，一种选择性的 nNOS 抑制剂，消除了 COX-1 免疫反应性 FG 标记的 PVN 神经元中脑肠肽诱导的 Fos 免疫反应性。脑肠肽还诱导了 PLA 阳性信号，表明 FG 标记的 PVN 神经元中 COX-1/nNOS 和 COX-1/S-亚硝基半胱氨酸的接近程度。