Antinociceptive effects induced by intra-periaqueductal grey administration of neuropeptide Y in rats

Hindpaw withdrawal latency (HWL) to thermal and mechanical stimulation increased dose-dependently after intra-periaqueductal grey (PAG) injection of neuropeptide Y (NPY). Furthermore, the NPY-induced increases in HWLs were attenuated by intra-PAG injection of the Y1 receptor antagonist NPY28-36. The results demonstrated that NPY plays an important role in antinociception in PAG, in which Y1 receptor is involved in.     

Heterogenous distribution of peptide-containing nerve fibres within the circular muscle layer of the human pylorus

The distribution of nerve fibres immunoreactive for vasoactive intestinal polypeptide (VIP), substance P (SP), methionine-enkephalin (ENK), calcitonin gene-related peptide (CGRP) and neuropeptide Y (NPY) within the circular muscle layer was examined histochemically in the human pylorus, adjacent antrum and duodenum. Longitudinal cryostat sections of the pyloric and surrounding regions were stained by an indirect immunofluorescence method, and the total length of each type of peptidecontaining fibre per unit sectional area (µm/mm²) was measured using an image-analysing system. The narrow region of the circular muscle layer bordering the submucosa in the pylorus contained a rich supply of VIP, SP, ENK and CGRP immunoreactive fibres; VIP fibres were most prominent with less SP and ENK fibres and moderate amounts of CGRP. These peptide-containing nerve fibres were more dense than in the pyloric circular muscle, the longitudinal muscle layer and also the adjacent muscle layer. NPY-immunoreactive fibres were sparsely distributed throughout the pyloric region. These results suggest that the inner edge of the circular muscle, lying adjacent to the submucosa and densely innervated with peptidecontaining fibres, may be a characteristic feature of the human pyloric sphincter.     

Pharmacological analysis of functional neurovascular transmission in canine splenic arteries: role of neuropeptide Y

1 The effects of neuropeptide Y (NPY) upon the isolated vasculature are reviewed. 2 The vasconstrictor responses to periarterial nerve stimulation (PNS) and neurotransmission by noradrenaline (NA) and ATP are discussed and illustrated using canine isolated perfused splenic artery. 3 Modulation of the vascular responses to PNS by NPY via pre- and post-junctional NPY Y2 and Y1 receptors is discussed. 4 Evidence is presented for different alpha1-adrenoceptor subtypes mediating vasoconstriction to exogenous and endogenously released NA and their different locations in the neurovascular junction and extrajunctional regions. 5 Activation of NPY Y1-receptors potentiates sympathetic nerve activated alpha1-adrenoceptor vasoconstriction. The proposal that the postjunctional alpha1B adrenoceptor may be linked to the NPY Y1-receptor and is responsible for co-operation between sympathetic and NPYergic interactions in the vasculature is discussed.     

Functional organization of the suprachiasmatic nucleus of Xenopus laevis in relation to background adaptation

The process of background adaptation in the toad Xenopus laevis is controlled by neurons in the suprachiasmatic nucleus (SC) that inhibit the release of alpha-melanophore-stimulating hormone from the neuroendocrine melanotrope cells in the pituitary gland. We have identified the structural and functional organization of different neuropeptide Y (NPY)-containing cell groups in the Xenopus SC in relation to background adaptation. A ventrolateral, a dorsomedial, and a caudal group were distinguished, differing in location as well as in number, size, and shape of their cells. They also show different degrees of NPY immunoreactivity in response to different background adaptation conditions. In situ hybridization using a Xenopus mRNA probe for the exocytosis protein DOC2 revealed that melanotrope cells of black-adapted animals have a much higher expression of DOC2-mRNA than white-adapted ones. This establishes that the degree of DOC2-mRNA expression is a good parameter to measure cellular secretory activity in Xenopus. We show that in the ventrolateral SC group, more NPY-positive neurons express DOC2-mRNA in white- than in black-adapted animals. In contrast, NPY-positive neurons in the dorsomedial group have a high secretory activity under the black-adaptation condition. We propose that in black-adapted animals, NPY-positive neurons in the ventrolateral group, known to inhibit the melanotrope cells in white-adapted animals synaptically, are inhibited by NPY-containing interneurons in the dorsmedial group. NPY-positive neurons in the caudal group have similar secretory dynamics as the dorsomedial NPY neurons, indicating that they also play a role in background adaptation, distinct from that exerted by the ventrolateral and dorsomedial group.     

Evolution of vertebrate neuropeptides

This review describes some of the most typical features in the evolution of neuropeptides. Neuropeptides are synthesized like other polypeptides and proteins, with an amino acid sequence determined by the DNA sequence of the corresponding gene. Mutations of bases in the coding regions of the DNA lead to changes in amino acid sequence, and explain the differences in amino acid sequence of a certain neuropeptide in different animal species. The more distantly related two species are, the more substitutions can be found in one and the same neuropeptide. The biologically active part of the neuropeptide is usually the most conserved part. Neuropeptides also form families of closely related peptides, where several members may occur in one animal species. This is due to gene or exon duplications followed by mutations. Gene splicing and posttranslational processing decides the gene product in a single cell. Difference in sequence may cause difference in function, but more often than not, members of a family appear to produce the same effect. Three neuropeptide families, the tachykinins, the neuropeptide Y family, and the vasoactive intestinal polypeptide/pituitary adenylate cyclase-activating peptide family will be described in more detail.     

吗啡依赖性大鼠海马CA1区NPY细胞阳性表达

目的 观察吗啡依赖性大鼠海马区NPY细胞的变化.方法 用皮下注射吗啡法建立雄性大鼠吗啡依赖模型.用免疫组织化学和图像分析方法观察大鼠CA1区NPY细胞的变化.结果 吗啡依赖性大鼠海马CA1区NPY细胞免疫反应减弱(p＜0.01).结论 NPY细胞减少与吗啡依赖性的发生、发展.     

通络生络方对急性脑梗死患者血浆VEGF、NPY含量的影响

目的观察急性脑梗死患者血浆血管内皮细胞生长因子(VEGF)和神经肽Y(NPY)含量在不同时间段的动态变化及通络生络方干预对其的影响。方法将65例患者随机分为对照组(30例,予甘露醇、阿司匹林、胞二磷胆碱治疗)和治疗组(35例,在西药治疗基础上加用通络生络方),在发病后第1d、3d、5d、10d,应用酶联免疫法和放射免疫法测定患者血浆VEGF和NPY含量。结果急性脑梗死患者血浆VEGF和NPY含量随发病时间延长逐渐增高,均于约第5d达到峰值。治疗组血浆VEGF含量一直保持在一个相对较高的水平,自发病第3d起与对照组比较,各时间段均有显著差异(P<0.01);治疗组自发病第3d起血浆NPY含量在不同时间段均明显低于对照组(P<0.01)。结论急性脑梗死后血浆VEGF和NPY含量均升高,通络生络方能够明显增加血浆VEGF含量,且使其维持在一个较高的水平,同时可以减少脑梗死后血浆NPY含量,这可能是通络生络方治疗急性脑梗死的机制之一。     

The hypothalamic-pituitary-thyroid axis in critical illness

In severe illness, profound changes occur in the hypothalamic-pituitary-thyroid axis. The observed decrease in serum concentration of both thyroid hormones and thyrotropin (TSH) are not compatible with a negative feedback loop and suggest a major change in setpoint regulation of the hypothalamic-pituitary-thyroid axis. This is supported by post mortem studies showing a decreased expression of thyrotropin-releasing hormone in the hypothalamic paraventricular nucleus of patients with a decreased serum T3 level. In critical illness, serum T3 may even become undetectable without giving rise to an elevated concentration of serum TSH. It is currently not clearly established whether this reflects an adaptation of the organism to illness or instead a potentially harmful condition leading to hypothyroidism at tissue level. There is thus a need for randomized clinical trials in critically ill patients to investigate whether they may benefit from a normalization of thyroid hormone concentration. Recent clinical studies in these patients involving the administration of hypothalamic peptides open up new ways of achieving this.     

神经肽Y1受体激动药诱导大鼠心肌细胞肥大的研究

 目的 探讨神经肽Y1受体激动药[Leu31,Pro34]NPY在诱导心肌细胞肥大中的作用.方法 用不同浓度[Leu31,Pro34]NPY刺激原代培养心肌细胞,采用放射性核素3H-leu掺入法检测培养心肌细胞蛋白质合成速率.应用荧光定量PCR方法检测[Leu31,Pro34]NPY对培养心肌细胞肥大相关基因ANF、β-MHC mRNA表达的影响.结果 [Leu31,Pro34]NPY(10-9 mol/L、10-8 mol/L、10-7 mol/L)作用心肌细胞24 h后可明显增加心肌细胞3H-leu的掺入量 (P＜0.01),并可诱导心肌细胞β-MHC表达增加(P＜0.01),对ANF表达的影响不明显.结论 神经肽Y1受体激动药[Leu31,Pro34]NPY可加快细胞蛋白质合成速率、促进心肌细胞β-MHC表达,直接诱导心肌细胞的肥大.