Presynaptic and Postsynaptic Effects of Neuropeptide Y in the Rat Pineal Gland

Abstract: Neuropeptide Y is colocalized with noradrena-line in sympathetic fibers innervating the rat pineal gland. In this article we present a study of the effects and mechanisms of action of neuropeptide Y on the pineal noradrenergic transmission, the main input leading to the rhythmic secretion of melatonin. At the presynaptic level, neuropeptide Y inhibits by 45%, with an EC₅₀ of 50 n M , the potassium-evoked noradrenaline release from pineal nerve endings. This neuropeptide Y inhibition occurs via the activation of pertussis toxin-sensitive G protein-coupled neuropeptide Y-Y2 receptors and is independent from, but additive to, the α₂-adrenergic inhibition of noradrenaline release. At the postsynaptic level, neuropeptide Y decreases by a maximum of 35%, with an EC₅₀ of 5 n M , the β-adrenergic induction of cyclic AMP elevation via the activation of neuropeptide Y-Y1 receptors. This moderate neuropeptide Y-induced inhibition of cyclic AMP accumulation, however, has no effect on the melatonin secretion induced by a β-adrenergic stimulation. On the contrary, in the presence of 1 m M ascorbic acid, neuropeptide Y potentiates (up to threefold) the melatonin secretion. In conclusion, this study has demonstrated that neuropeptide Y modulates the noradrenergic transmission in the rat pineal gland at both presynaptic and postsynaptic levels, using different receptor subtypes and transduction pathways.     

Relation of neuropeptide Y gene expression and genotyping with hypertension in chronic kidney disease

ObjectivesThe prognosis of high-risk patients might be greatly ameliorated using genetic predisposition risk factors. Sympathetic activity and innate immunity related to neuropeptide Y function may be related to dyslipidemia and atherosclerosis. The aim of this study is to detect the correlation between Neuropeptide Y (NPY) SNP rs16147 and its gene expression in chronic kidney disease with and without hypertension.MethodsThis study carried out on 150 subjects who were divided into 3 main groups group (I) 50 CKD patients with hypertension, group (II) 50 CKD patients without hypertension and group (III) 50 healthy individuals. Carotid intima media thickness (CIMT) was measured by Ultrasound. Kidney function test and lipid profile were performed. Genotyping and gene expression of neuropeptide Y (NPY) were performed using real time PCR.ResultsThere was a significant increase in number and percentage of CC genotype and C allele of NPY SNP distribution in CKD patients with and without hypertension when compared to controls. A significant association was found between CC genotype and C allele and the risk of CKD with hypertension with odd ratio 3.26 and 1.77, respectively. There is a significant positive correlation between NPY gene expression level and CIMT among chronic kidney disease patients with highest level of TC, LDLc and CIMT among CC genotype of NPY gene.ConclusionA significant association was found between CC genotype and C allele of NPY at rs16147 with increase NPY gene expression and risk of developing hypertension in CKD.     

Effect of myrrh and thyme on Trichinella spiralis enteral and parenteral phases with inducible nitric oxide expression in mice

Trichinellosis is a serious disease with no satisfactory treatment. We aimed to assess the effect of myrrh (Commiphora molmol) and, for the first time, thyme (Thymus vulgaris L.) against enteral and encysted (parenteral) phases of Trichinella spiralis in mice compared with albendazole, and detect their effect on inducible nitric oxide synthase (iNOS) expression. Oral administration of 500 mg/kg of myrrh and thyme led to adult reduction (90.9%, 79.4%), while 1,000 mg/kg led to larvae reduction (79.6%, 71.3%), respectively. Administration of 50 mg/kg of albendazole resulted in adult and larvae reduction (94.2%, 90.9%). Positive immunostaining of inflammatory cells infiltrating intestinal mucosa and submucosa of all treated groups was detected. Myrrh-treated mice showed the highest iNOS expression followed by albendazole, then thyme. On the other hand, both myrrh and thyme-treated groups showed stronger iNOS expression of inflammatory cells infiltrating and surrounding encapsulated T. spiralis larvae than albendazole treated group. In conclusion, myrrh and thyme extracts are highly effective against both phases of T. spiralis and showed strong iNOS expressions, especially myrrh which could be a promising alternative drug. This experiment provides a basis for further exploration of this plant by isolation and retesting the active principles of both extracts against different stages of T. spiralis.     

Blocking the QB‐binding site of photosystem II by tenuazonic acid,a non–host‐specific toxin of Alternaria alternata,activates singlet oxygen‐mediated and EXECUTER‐dependent signalling in Arabidopsis

Necrotrophic fungal pathogens produce toxic compounds that induce cell death in infected plants. Often, the primary targets of these toxins and the way a plant responds to them are not known. In the present work, the effect of tenuazonic acid (TeA), a non–host‐specific toxin of Alternaria alternata, on Arabidopsis thaliana has been analysed. TeA blocks the Q_B‐binding site at the acceptor side of photosystem II (PSII). As a result, charge recombination at the reaction centre (RC) of PSII is expected to enhance the formation of the excited triplet state of the RC chlorophyll that promotes generation of singlet oxygen (¹O₂). ¹O₂ activates a signalling pathway that depends on the two EXECUTER (EX) proteins EX1 and EX2 and triggers a programmed cell death response. In seedlings treated with TeA at half‐inhibition concentration ¹O₂‐mediated and EX‐dependent signalling is activated as indicated by the rapid and transient up‐regulation of ¹O₂‐responsive genes in wild type, and its suppression in ex1/ex2 mutants. Lesion formation occurs when seedlings are exposed to higher concentrations of TeA for a longer period of time. Under these conditions, the programmed cell death response triggered by ¹O₂‐mediated and EX‐dependent signalling is superimposed by other events that also contribute to lesion formation.     

DNA evolutionary rates in nine-primaried passerine birds

Differences in single-copy nuclear-DNA sequences among 13 species of passerine birds were measured using DNA-DNA hybridization. A matrix of pairwise dissimilarity values (delta mode distances) was constructed from analysis of fitted thermal dissociation curves. A least-squares method of phylogenetic estimation was used to construct two topologies from the distance matrix, one constraining branch lengths of sister taxa to be equal and the other permitting such lengths to vary. These topologies were identical in the pattern of branching of taxa, and the difference in their sums of squares was not statistically significant, suggesting that rates of DNA evolution in sister groups of nine- primaried oscines are equal. A nonparametric test for nonrandom variation in distances of sister groups to outgroup taxa revealed no statistically significant deviation from random variation that would be expected as a result of measurement error. However, the level of measurement error was such that rates of DNA evolution in sister taxa could vary by as much as 10% without being detected with the statistical methods used here.      

脑电信号数据压缩及棘波识别的小波神经网络方法

本文在对小波神经网络及其算法研究的基础上,提出了一种对脑电信号压缩表达和痫样脑电棘波识别的新方法。实验结果显示,小波网络在大量压缩数据的同时,能够较好的恢复原有信号,另外,在脑电信号的时频谱等高线图上,得到了易于自动识别的棘波和棘慢复合波特征,说明此方法在电生理信号处理和时频分析方面有着光明的应用前景。     

14-3-3 proteins double the number of outward-rectifying K+ channels available for activation in tomato cells

Outward-rectifying K+ channels are modulated in response to environmental stimuli by a range of intracellular factors, such as cytoplasmic Ca2+, pH, kinases and phosphatases. Here we report that voltage-dependent outward-rectifying K+ channels in tomato cells are also targets for modulation by 14-3-3 proteins. In whole-cell patch-clamp experiments, recombinant 14-3-3 protein (tomato isoform TFT7) was introduced into tomato cell protoplasts via the patch pipette. As a result the steady-state outward K+ current increased twofold and this increase was not dependent upon the presence of cytoplasmic ATP. A phosphorylated peptide that contained a phosphorylated 14-3-3 target-binding motif (RSTS*TP), derived from nitrate reductase, blocked the effect of 14-3-3, thus showing the specific nature of 14-3-3 action. Kinetic parameters of the conductance, like (de)activation kinetics, voltage dependence of gating and activation potential, were not significantly different between control and 14-3-3 infused cells. Analysis of single-channel activity and whole-cell noise indicated that the single-channel conductance was not affected by 14-3-3 infusion. We conclude that 14-3-3 proteins recruit 'sleepy' channels into a voltage-activatable state. The molecular mechanism underlying the 1 : 1 ratio of constitutively active and 14-3-3 recruited channels is discussed in the light of known functions of 14-3-3 dimers.     

Longitudinal proxy measurements in multiple sclerosis: patient-proxy agreement on the impact of MS on daily life over a period of two years

Background  

The use of self-report measurements in clinical settings is increasing. However, in patients with limitations that interfere with reliable self-assessment such as cognitive impairment or mood disturbances, as may be the case in multiple sclerosis (MS), data collection might be problematic. In these situations, information obtained from proxy respondents (e.g. partners) may replace self-ratings. The aim of this study was to examine the value of proxy ratings at separate points in time and to assess patient-proxy agreement on possible changes in disease impact of MS.     

Benthic freshwater nematode community dynamics under conditions of Tilapia aquaculture in Egypt

Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, from July to November 2014 under conditions of irrigation (reference), fish farm pond with high Tilapia density, and fish farm pond effluent canal without fish. The nematode genera Adoncholaimus, Punctodora, Labronema, Oncholaimus and Odontolaimus were present at all sites. Environmental factors were not related to nematode distribution patterns. Tilapia predation and/or disturbance may explain reduced nematode abundance, especially of the largest genera, Adoncholaimus, Punctodora and Labronema at the fish farm site. The absence of fish from the drainage site allowed intergeneric nematode competitive exclusion, benefitting the largest nematodes and reducing diversity indices.