NEUROREGULATORY ASPECTS OF NEUROMEDIN B

神经介肽B是唯一已知的哺乳动物肽， 蛙皮素家族的蛙皮素/litorin亚组，并含有 与蛙皮素的同源性为70%。 三种氨基酸 取代足以为肽提供独特的生物活性。 一系列生理特征。 给予神经介肽B 在幽门结扎的大鼠中，ICV甚至不能减少胃分泌， 虽然它是一种真正的神经肽，在脑内分布广泛， 组织. 在解剖的大脑区域提取物中， 通过放射免疫测定发现广泛分布： 垂体（后叶大于前叶）， 边缘系统（下丘脑大于海马， 而不是丘脑）和其他脑区域（尾状核、大脑 皮质、黑质、脑干）。 这些结果进一步 免疫组化定位证实， 神经介肽B在整个大鼠脑的神经细胞中的表达。 初步 数据表明存在神经介肽B染色细胞层 在大脑皮层的冠状区域有散在的细胞 在底层，单个细胞分散在 海马体的锥体区， 下丘脑腹内侧，和分散的细胞体与长 脑干网状网中的轴突 应用四 多克隆抗体显示， 检测依赖于一个位点的特异性， 特定抗体以及提取条件 就业。 等度HPLC进一步显示，每个多克隆 抗体识别不同分子形式的 大鼠脊髓神经介素B免疫反应性 数据还 表明脑垂体和边缘系统中神经介肽B水平 在哺乳期女性中， 在断奶期间，除了下丘脑，下丘脑仍然在 抑郁状态 总的来说，证据表明， 神经介肽B的分布定义了一种新的神经通路 这可能涉及到自治系统中的调节能力， 神经系统和受荷尔蒙控制。

Neuromedin B is the only known mammalian peptide of the ranatensin/litorin subgroup of the bombesin family and contains 70% homology with bombesin. The three amino acid substitutions are sufficient to provide the peptide with a unique set of physiological characteristics. Neuromedin B administered icv in pylorus-ligated rats failed to reduce gastric secretion even though it is a true neuropeptide with wide distribution in brain tissue. In extracts of dissected brain regions, the peptide was found by radioimmunoassays to be widely distributed: the pituitary gland (posterior lobe greater than anterior portion), the limbic system (hypothalamus greater than hippocampus greater than thalamus), and other brain regions (caudate, cerebral cortex, substantia nigra, brain stem). These results were further confirmed by the immunohistochemical localization of neuromedin B in nerve cells throughout rat brain. Preliminary data indicate the presence of a neuromedin B staining cell layer in the coronal region of the cerebral cortex with scattered cells in the underlying layers, individuals cells dispersed among the pyramidal region of the hippocampus, a nucleus in the ventromedial hypothalamus, and dispersed cell bodies with long axons in the reticular net of the brain stem. Application of four polyclonal antibodies revealed that the amount of peptide detected depends upon the site-directed specificity of a particular antibody as well as the extraction conditions employed. Isocratic HPLC further revealed that each polyclonal antibody recognized different molecular forms of immunoreactive neuromedin B in rat spinal cord. Data also indicate that neuromedin B levels in the pituitary and limbic region decrease dramatically in lactating females and rise slowly during weaning, except in the hypothalamus which remains at the depressed state. In toto, the evidence suggests that pattern and distribution of neuromedin B defines a new neuronal pathway which may be involved in a regulatory capacity in the autonomic nervous system and subject to hormonal control.